Patent Publication Number: US-10770864-B2

Title: Surface emitting laser

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation application of application Ser. No. 15/652,397, filed on Jul. 18, 2017 with claiming foreign priority of TW105122579. The prior application is herewith incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     Technical Field 
     The instant disclosure relates to a surface emitting laser, in particular, to a surface emitting laser with improved efficiency. 
     Related Art 
     Laser is an important development in photoelectric industries. Lasers are widely used in many manufacturing industries, e.g., laser cutting machines, laser engraving machines, laser rangefinders. Lasers may be divided into surface emitting lasers and edge emitting lasers. Currently, because the manufacturing process for surface emitting lasers is rather simpler as compared to that for edge emitting lasers and the surface emitting lasers can be provided for testing right after the manufactured, surface emitting lasers are main stream in the developments of laser. 
     A surface emitting laser is deposited or grown by epitaxial growth method provided in semiconductor manufacturing processes, e.g., metal organic chemical-vapor deposition (MOCVD), vapor phase epitaxy (VPE), liquid phase epitaxy (LPE), or molecular beam epitaxy (MBE), and is manufactured by combinations of steps, e.g., photolithography, etching process, lift-off process, thin film deposition process, metal film deposition process, spin process, alloy process, wafer bonding process, and laser lift-off process. In the surface emitting laser, a current-blocking layer is manufactured between the laser emitting structure and the distributed Bragg reflector (DBR, for the sake of convenience, hereinafter called DBR layer) to confine currents to form an electric field within the laser emitting structure to generate a light beam, and the light beam is further reflected by the DBR layer to form resonance gain and then is emitted in the form of laser. The current-blocking layer is used to confine currents to form an electric field within the laser emitting structure to allow the surface emitting laser emitting laser beams. Therefore, the current-blocking layer is quite important. 
     In a conventional manufacturing method for the current-blocking layer, the surface of the laser emitting structure layer is oxidized to form an oxidized structure, and the oxidized structure is insulated. However, since the oxidation process cannot be controlled properly, the quality of the oxidized structure varies. As a result, the current-blocking layer cannot block currents efficiently. In addition, because the oxidized structure is formed by oxidation, the oxidized structure is inflated and deformed. As a result, the combination between the DBR layer and the laser emitting structure layer becomes worse and the DBR layer may be ablated from the laser emitting structure layer. Consequently, the efficiency of the surface emitting laser worsens. 
     In another conventional manufacturing method for the current-blocking layer, the uppermost part of the laser emitting structure layer is defined as the current-blocking layer by an ion implantation process. In the ion implantation process, hydrogen ions are implanted on the laser emitting structure layer to break the bonding of the uppermost part of the laser emitting structure layer, so that the uppermost of the laser emitting structure layer is insulated. However, the ion implantation method would make the surface of the uppermost part of the laser emitting structure layer rough. As a result, the interface between the DBR layer and the laser emitting structure layer is very uneven, so that the reflection rate of the DBR layer is reduced. Moreover, the implanted depth of the hydrogen ions cannot be controlled properly; when the implanted depth is too deep, the laser emitting structure layer would be damaged, while when the implanted depth is too shallow, the performance for blocking current of the current-blocking layer would worsen. 
     As above, the conventional manufacturing methods for the current-blocking layer are destructive manufacturing methods. However, neither the oxidation process nor the ion implantation process can be controlled properly, thus the quality of the manufactured current-blocking layers varies. As a result, the surface emitting lasers may have structural defects which worsen the performance of the surface emitting laser. 
     SUMMARY 
     In view of the aforementioned problems in manufacturing the current-blocking layer, a surface emitting laser is provided, according to the instant disclosure. The current-blocking layer is grown by semiconductor epitaxy process. Hence, the laser structure layer in the laser can be properly combined with other layers to improve the efficiency of the surface emitting laser. 
     In one embodiment, a surface emitting laser comprises a conductive substrate; a metal bonding layer on an upper surface of the conductive substrate; a laser structure layer on an upper surface of the metal bonding layer, wherein the laser structure layer has a first epitaxial current-blocking layer, and the first epitaxial current-blocking layer has a first current opening for current passing; an epitaxial semiconductor reflection layer on an upper surface of the laser structure layer; a first electrode layer on an upper surface of the epitaxial semiconductor reflection layer for packaging and electrical conduction; wherein the first epitaxial current-blocking layer is grown by a semiconductor epitaxy process, and a type of a semiconductor material of the first epitaxial current-blocking layer is different from a type of a semiconductor material of the laser structure layer; wherein the surface emitting laser further comprises two conductive metals, portions of the metal bonding layer respectively corresponding to the two sides of the first current opening form two recessed grooves; the conductive metals are in the recessed grooves, respectively; surfaces of the conductive metals are flush with a surface of the metal bonding layer and bonded to the laser structure layer. 
     In another embodiment, a surface emitting laser comprises a conductive substrate; a metal bonding layer on an upper surface of the conductive substrate; a laser structure layer on an upper surface of the metal bonding layer, wherein the laser structure layer has a first epitaxial current-blocking layer, and the first epitaxial current-blocking layer has a first current opening for current passing; an epitaxial semiconductor reflection layer on an upper surface of the laser structure layer; a first electrode layer on an upper surface of the epitaxial semiconductor reflection layer for packaging and electrical conduction; wherein the first epitaxial current-blocking layer is grown by a semiconductor epitaxy process, and a type of a semiconductor material of the first epitaxial current-blocking layer is different from a type of a semiconductor material of the laser structure layer; wherein the surface emitting laser further comprises a transparent conductive layer and a first conductive metal; the transparent conductive layer is between the metal bonding layer and the laser structure layer; a first portion of the transparent conductive layer corresponding to the first current opening forms a first recessed groove; the first conductive metal is in the first recessed groove, and a surface of the first conductive metal is flush with a surface of the transparent conductive layer and bonded to the laser structure layer. 
     In another embodiment, a surface emitting laser comprises a conductive substrate; a metal bonding layer on an upper surface of the conductive substrate; a laser structure layer on an upper surface of the metal bonding layer, wherein the laser structure layer has a first epitaxial current-blocking layer, and the first epitaxial current-blocking layer has a first current opening for current passing; an epitaxial semiconductor reflection layer on an upper surface of the laser structure layer; a first electrode layer on an upper surface of the epitaxial semiconductor reflection layer for packaging and electrical conduction; wherein the first epitaxial current-blocking layer is grown by a semiconductor epitaxy process, and a type of a semiconductor material of the first epitaxial current-blocking layer is different from a type of a semiconductor material of the laser structure layer; wherein the surface emitting laser further comprises a transparent conductive layer, a first conductive metal, and an insulating layer; the transparent conductive layer is between the metal bonding layer and the laser structure layer, the first conductive metal is on a first portion of the transparent conductive layer corresponding to the first current opening, and the first conductive metal corresponds to the first current opening; the insulating layer is on a surface of the transparent conductive layer and surrounds the first conductive metal; a surface of the insulating layer is flush with a surface of the first conductive metal and bonded to the laser structure layer. 
     In another embodiment, A surface emitting laser comprises a conductive substrate; a metal bonding layer on an upper surface of the conductive substrate; a laser structure layer on an upper surface of the metal bonding layer, wherein the laser structure layer has a first epitaxial current-blocking layer, and the first epitaxial current-blocking layer has a first current opening for current passing; an epitaxial semiconductor reflection layer on an upper surface of the laser structure layer; a first electrode layer on an upper surface of the epitaxial semiconductor reflection layer for packaging and electrical conduction; wherein the first epitaxial current-blocking layer is grown by a semiconductor epitaxy process, and a type of a semiconductor material of the first epitaxial current-blocking layer is different from a type of a semiconductor material of the laser structure layer; wherein the surface emitting laser further comprises a transparent conductive layer and a layer of conductive metal; the transparent conductive layer is between the metal bonding layer and the laser structure layer, the layer of conductive metal is between the transparent conductive layer and the laser structure layer; the layer of conductive metal is a whole layer corresponding to the transparent conductive layer and the laser structure layer. 
     Accordingly, because the epitaxial current-blocking layer in the laser structure layer is grown by the semiconductor epitaxy process, neither the uncontrollable oxidation manufacturing method nor the ion implantation method are needed for making the current-blocking layer. Hence, the problem of unwanted inflation of the laser structure layer and the problem of ablation of the laser structure layer from the epitaxial semiconductor reflection layer caused by the uncontrollable oxidation method can be prevented, and the problem of the unsmooth surface of the laser structure layer caused by the ion implantation method can be prevented. The smooth structure of the epitaxial current-blocking layer allows the structure of the laser structure layer to be smooth, so that the junction interface between the laser structure layer and the epitaxial semiconductor reflection layer can be proper combined to improve the efficiency of the surface emitting laser. 
     In yet another embodiment, A surface emitting laser comprises a conductive substrate; a first epitaxial semiconductor reflection layer on an upper surface of the conductive substrate; a metal bonding layer between the conductive substrate and the first epitaxial semiconductor reflection layer; a laser structure layer on an upper surface of the first epitaxial semiconductor reflection layer, wherein the laser structure layer has a first epitaxial current-blocking layer, and the first epitaxial current-blocking layer has a first current opening for current passing; a second epitaxial semiconductor reflection layer on an upper surface of the laser structure layer; a first electrode layer on the upper surface of the laser structure layer for packaging and electrical conduction; wherein the first epitaxial current-blocking layer is grown by a semiconductor epitaxy process, and a type of a semiconductor material of the first epitaxial current-blocking layer is different from a type of a semiconductor material of the laser structure layer; wherein the surface emitting laser further comprises two conductive metals, portions of the metal bonding layer respectively corresponding to the two sides of the first current opening form two recessed grooves; the conductive metals are in the recessed grooves, respectively; surfaces of the conductive metals are flush with a surface of the metal bonding layer and bonded to the first epitaxial semiconductor reflection layer. 
     In another embodiment, a surface emitting laser comprises a conductive substrate; a first epitaxial semiconductor reflection layer on an upper surface of the conductive substrate; a metal bonding layer between the conductive substrate and the first epitaxial semiconductor reflection layer; a laser structure layer on an upper surface of the first epitaxial semiconductor reflection layer, wherein the laser structure layer has a first epitaxial current-blocking layer, and the first epitaxial current-blocking layer has a first current opening for current passing; a second epitaxial semiconductor reflection layer on an upper surface of the laser structure layer; a first electrode layer on the upper surface of the laser structure layer for packaging and electrical conduction; wherein the first epitaxial current-blocking layer is grown by a semiconductor epitaxy process, and a type of a semiconductor material of the first epitaxial current-blocking layer is different from a type of a semiconductor material of the laser structure layer; wherein the surface emitting laser further comprises a transparent conductive layer and a first conductive metal; the transparent conductive layer is between the metal bonding layer and the first epitaxial semiconductor reflection layer; a first portion of the transparent conductive layer corresponding to the first current opening forms a first recessed groove; the first conductive metal is in the first recessed groove, and a surface of the first conductive metal is flush with a surface of the transparent conductive layer and bonded to the first epitaxial semiconductor reflection layer. 
     In another embodiment, a surface emitting laser comprises a conductive substrate; a first epitaxial semiconductor reflection layer on an upper surface of the conductive substrate; a metal bonding layer between the conductive substrate and the first epitaxial semiconductor reflection layer; a laser structure layer on an upper surface of the first epitaxial semiconductor reflection layer, wherein the laser structure layer has a first epitaxial current-blocking layer, and the first epitaxial current-blocking layer has a first current opening for current passing; a second epitaxial semiconductor reflection layer on an upper surface of the laser structure layer; a first electrode layer on the upper surface of the laser structure layer for packaging and electrical conduction; wherein the first epitaxial current-blocking layer is grown by a semiconductor epitaxy process, and a type of a semiconductor material of the first epitaxial current-blocking layer is different from a type of a semiconductor material of the laser structure layer; wherein the surface emitting laser further comprises a transparent conductive layer, a first conductive metal, and an insulating layer; the transparent conductive layer is between the metal bonding layer and the first epitaxial semiconductor reflection layer; the first conductive metal is on a first portion of the transparent conductive layer corresponding to the first current opening, and the first conductive metal corresponds to the first current opening; the insulating layer is on a surface of the transparent conductive layer and surrounds the first conductive metal; a surface of the insulating layer is flush with a surface of the first conductive metal and bonded to the first epitaxial semiconductor reflection layer. 
     In another embodiment, a surface emitting laser comprises a conductive substrate; a first epitaxial semiconductor reflection layer on an upper surface of the conductive substrate; a metal bonding layer between the conductive substrate and the first epitaxial semiconductor reflection layer; a laser structure layer on an upper surface of the first epitaxial semiconductor reflection layer, wherein the laser structure layer has a first epitaxial current-blocking layer, and the first epitaxial current-blocking layer has a first current opening for current passing; a second epitaxial semiconductor reflection layer on an upper surface of the laser structure layer; a first electrode layer on the upper surface of the laser structure layer for packaging and electrical conduction; wherein the first epitaxial current-blocking layer is grown by a semiconductor epitaxy process, and a type of a semiconductor material of the first epitaxial current-blocking layer is different from a type of a semiconductor material of the laser structure layer; wherein the surface emitting laser further comprises a transparent conductive layer and a layer of conductive metal; the transparent conductive layer is between the metal bonding layer and the first epitaxial semiconductor reflection layer, the layer of conductive metal is between the transparent conductive layer and the first epitaxial semiconductor reflection layer; the layer of conductive metal is a whole layer corresponding to the transparent conductive layer and the first epitaxial semiconductor reflection layer. 
     Accordingly, because the epitaxial current-blocking layer in the laser structure layer is grown by the semiconductor epitaxy process, neither the uncontrollable oxidation manufacturing method nor the ion implantation method are needed for making the current-blocking layer. Hence, the problem of unwanted inflation of the laser structure layer and the problem of ablation of the laser structure layer from the first and second epitaxial semiconductor reflection layers caused by the uncontrollable oxidation method can be prevented, and the problem of the unsmooth surface of the laser structure layer caused by the ion implantation method can be prevented. The smooth structure of the epitaxial current-blocking layer allows the structure of the laser structure layer to be smooth, so that the junction interface between the laser structure layer and the first and second epitaxial semiconductor reflection layers can be proper combined to improve the efficiency of the surface emitting laser. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus not limitative of the disclosure, wherein: 
         FIG. 1  illustrates a structural view of a first embodiment of the instant disclosure; 
         FIG. 2-1  illustrates another structural view of the first embodiment; 
         FIG. 2-2  illustrates yet another structural view of the first embodiment; 
         FIG. 3  illustrates a structural view of a second embodiment of the instant disclosure; 
         FIG. 4  illustrates a structural view of a third embodiment of the instant disclosure; 
         FIG. 5  illustrates a structural view of a fourth embodiment of the instant disclosure; 
         FIG. 6  illustrates a structural view of a fifth embodiment of the instant disclosure; 
         FIG. 7  illustrates a structural view of a sixth embodiment of the instant disclosure; 
         FIG. 8  illustrates a structural view of a seventh embodiment of the instant disclosure; 
         FIG. 9  illustrates a structural view of an eighth embodiment of the instant disclosure; 
         FIG. 10  illustrates a structural view of a ninth embodiment of the instant disclosure; 
         FIG. 11  illustrates a structural view of a tenth embodiment of the instant disclosure; 
         FIG. 12  illustrates a structural view of an eleventh embodiment of the instant disclosure; 
         FIG. 13  illustrates a structural view of a twelfth embodiment of the instant disclosure; 
         FIG. 14  illustrates a structural view of a thirteenth embodiment of the instant disclosure; 
         FIG. 15  illustrates a structural view of a fourteenth embodiment of the instant disclosure; 
         FIG. 16  illustrates a structural view of a fifteenth embodiment of the instant disclosure; 
         FIG. 17  illustrates a structural view of a sixteenth embodiment of the instant disclosure; 
         FIG. 18  illustrates a structural view of a seventeenth embodiment of the instant disclosure; 
         FIG. 19  illustrates a structural view of an eighteenth embodiment of the instant disclosure; 
         FIG. 20  illustrates a structural view of a nineteenth embodiment of the instant disclosure; 
         FIG. 21  illustrates a structural view of a twentieth embodiment of the instant disclosure; 
         FIG. 22  illustrates a structural view of a twenty-first embodiment of the instant disclosure; 
         FIG. 23  illustrates a structural view of a twenty-second embodiment of the instant disclosure; 
         FIG. 24  illustrates a structural view of a twenty-third embodiment of the instant disclosure; 
         FIG. 25  illustrates a structural view of a twenty-fourth embodiment of the instant disclosure; 
         FIG. 26  illustrates a structural view of a twenty-fifth embodiment of the instant disclosure; 
         FIG. 27  illustrates a structural view of a twenty-sixth embodiment of the instant disclosure; 
         FIG. 28  illustrates a structural view of a twenty-seventh embodiment of the instant disclosure; 
         FIG. 29  illustrates a structural view of a twenty-eighth embodiment of the instant disclosure; 
         FIG. 30  illustrates a structural view of a twenty-ninth embodiment of the instant disclosure; 
         FIG. 31  illustrates a structural view of a thirtieth embodiment of the instant disclosure; 
         FIG. 32  illustrates a structural view of a thirty-first embodiment of the instant disclosure; 
         FIG. 33  illustrates a structural view of a thirty-second embodiment of the instant disclosure; 
         FIG. 34  illustrates a structural view of a thirty-third embodiment of the instant disclosure; 
         FIG. 35  illustrates a structural view of a thirty-fourth embodiment of the instant disclosure; 
         FIG. 36  illustrates a structural view of a thirty-fifth embodiment of the instant disclosure; 
         FIG. 37  illustrates a structural view of a thirty-sixth embodiment of the instant disclosure; 
         FIG. 38  illustrates a structural view of a thirty-seventh embodiment of the instant disclosure; 
         FIG. 39  illustrates a structural view of a thirty-eighth embodiment of the instant disclosure; 
         FIG. 40  illustrates a structural view of a thirty-ninth embodiment of the instant disclosure; 
         FIG. 41  illustrates a structural view of a fortieth embodiment of the instant disclosure; 
         FIG. 42  illustrates a structural view of a forty-first embodiment of the instant disclosure; 
         FIG. 43  illustrates a structural view of a forty-second embodiment of the instant disclosure; 
         FIG. 44  illustrates a structural view of a forty-third embodiment of the instant disclosure; 
         FIG. 45  illustrates a structural view of a forty-fourth embodiment of the instant disclosure; 
         FIG. 46  illustrates a structural view of a forty-fifth embodiment of the instant disclosure; 
         FIG. 47  illustrates a structural view of a forty-sixth embodiment of the instant disclosure; 
         FIG. 48  illustrates a structural view of a forty-seventh embodiment of the instant disclosure; 
         FIG. 49  illustrates a structural view of a forty-eighth embodiment of the instant disclosure; 
         FIG. 50  illustrates a structural view of a forty-ninth embodiment of the instant disclosure; 
         FIG. 51  illustrates a structural view of a fiftieth embodiment of the instant disclosure; 
         FIG. 52  illustrates a structural view of a fifty-first embodiment of the instant disclosure; 
         FIG. 53  illustrates a structural view of a fifty-second embodiment of the instant disclosure; 
         FIG. 54  illustrates a structural view of a fifty-third embodiment of the instant disclosure; 
         FIG. 55  illustrates a structural view of a fifty-fourth embodiment of the instant disclosure; 
         FIG. 56  illustrates a structural view of a fifty-fifth embodiment of the instant disclosure; 
         FIG. 57  illustrates a structural view of a fifty-sixth embodiment of the instant disclosure; 
         FIG. 58  illustrates a structural view of a fifty-seventh embodiment of the instant disclosure; 
         FIG. 59  illustrates a structural view of a fifty-eighth embodiment of the instant disclosure; 
         FIG. 60  illustrates a structural view of a fifty-ninth embodiment of the instant disclosure; 
         FIG. 61  illustrates a structural view of a sixtieth embodiment of the instant disclosure; 
         FIG. 62  illustrates a structural view of a sixty-first embodiment of the instant disclosure; 
         FIG. 63  illustrates a structural view of a sixty-second embodiment of the instant disclosure; and 
         FIG. 64  illustrates a structural view of a sixty-third embodiment of the instant disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1 , illustrating a surface emitting laser with improved efficiency according to a first embodiment of the instant disclosure. The surface emitting laser comprises a conductive substrate  10 , a metal bonding layer  11 , a laser structure layer  20 , an epitaxial semiconductor reflection layer  12 , and a first electrode layer  13 . The laser structure layer  20 , the epitaxial semiconductor reflection layer  12 , and the first electrode layer  13  form a surface-emitting type laser structure. The surface-emitting type laser structure is manufactured by a semiconductor epitaxy process and a semiconductor manufacturing process. In this embodiment, the semiconductor epitaxy process may be a metal organic chemical-vapor deposition (MOCVD) process, and the semiconductor manufacturing process may be combinations of photolithography, etching process, lift-off process, thin film deposition process, metal film deposition process, spin process, alloy process, wafer bonding process, laser lift-off process, etc. 
     In this embodiment, the conductive substrate  10  is an electrically conductive substrate with great heat dissipation and electrical conductive properties. The conductive substrate  10  may be made of molybdenum, gallium phosphide, silicon, aluminum, or copper. 
     In this embodiment, the combination between the surface-emitting type laser structure and the conductive substrate  10  may be accomplished by a wafer bonding process. In the wafer bonding process, firstly the metal bonding layer  11  is disposed on an upper surface of the conductive substrate  10 . Next, after a substrate for loading the surface-emitting type laser structure is removed, the surface-emitting type laser structure is transferred to an upper surface of the metal bonding layer  11  to form the surface emitting laser. In this embodiment, a second electrode layer  14  is disposed on a lower surface of the conductive substrate  10 . 
     In this embodiment, the metal bonding layer  11  is used to connect the laser structure layer  20  with the conductive substrate  10 . The metal bonding layer  11  may be used for electrical conduction and for reflecting the light generated by the laser structure layer  20 , so that the light can be resonated back and forth between the metal bonding layer  11  and the epitaxial semiconductor reflection layer  12  to form resonance gain. As a result, the light can be emitted in the form of laser eventually. 
     The epitaxial semiconductor reflection layer  12  may be formed by stacking two semiconductor materials with different reflection indexes to form a distributed Bragg reflector. 
     The first electrode layer  13  and the second electrode layer  14  are for receiving voltage/current for testing and for electrical connection in the subsequent packaging process. The type of the semiconductor material of the second electrode layer  14  is different from the type of the semiconductor material of the first electrode layer  13 , and the first electrode layer  13  and the second electrode layer  14  have different electrical polarities. When the first electrode layer  13  is a positive electrode, the second electrode layer  14  is a negative electrode. Conversely, when the first electrode layer  13  is a negative electrode, the second electrode layer  14  is a positive electrode. 
     The laser structure layer  20  has a first epitaxial current-blocking layer  21 , and a middle portion of the first epitaxial current-blocking layer  21  has a first current opening  211 , so that the currents only passes through the first current opening  211 . In this embodiment, the laser structure layer  20  sequentially has, from a top to a bottom, a first semiconductor epitaxial layer  22 , an emitting reaction active layer  23 , and a second semiconductor epitaxial layer  24  on the upper surface of the metal bonding layer  11 , and the first epitaxial current-blocking layer  21  is in the first semiconductor epitaxial layer  22 . In this embodiment, the type of the semiconductor material of the first semiconductor epitaxial layer  22  is opposite to the type of the semiconductor material of the second semiconductor epitaxial layer  24 . When the first semiconductor epitaxial layer  22  is a P type semiconductor, the second semiconductor epitaxial layer  24  is an N type semiconductor. Conversely, when the first semiconductor epitaxial layer  22  is an N type semiconductor, the second semiconductor epitaxial layer  24  is a P type semiconductor. 
     In this embodiment, the epitaxial semiconductor reflection layer  12  may be a P-type semiconductor reflection layer or an N-type semiconductor reflection layer. The type of the semiconductor material of the epitaxial semiconductor reflection layer  12  corresponds to the type of the semiconductor material of the second semiconductor epitaxial layer  24 . When the second semiconductor epitaxial layer  24  is an N type semiconductor, the epitaxial semiconductor reflection layer  12  is an N type semiconductor reflection layer. Conversely, when the second semiconductor epitaxial layer  24  is a P type semiconductor, the epitaxial semiconductor reflection layer  12  is a P type semiconductor reflection layer. 
     Please refer to  FIGS. 2-1 and 2-2 . The first epitaxial current-blocking layer  21  may be grown by a semiconductor epitaxy process. The first epitaxial current-blocking layer  21  may be formed by an N type semiconductor layer or a P type semiconductor layer. Alternatively, the first epitaxial current-blocking layer  21  may be formed by three of more layers including both N type and P type semiconductor layers. The N type and P type semiconductor layers are stacked with one another in an interlacing manner, and a total number of the stacked N type and P type semiconductor layers of the first epitaxial current-blocking layer  21  is an odd number. 
     In this embodiment, the first epitaxial current-blocking layer  21  may be an N type semiconductor layer or a P type semiconductor layer. The type of the semiconductor material of the first epitaxial current-blocking layer  21  is opposite to the type of the semiconductor material of the first semiconductor epitaxial layer  22 . That is, when the first semiconductor epitaxial layer  22  is an N type semiconductor, the first epitaxial current-blocking layer  21  is a P type semiconductor; conversely, when the first semiconductor epitaxial layer  22  is a P type semiconductor, the first epitaxial current-blocking layer  21  is an N type semiconductor. 
     In this embodiment, when the first epitaxial current-blocking layer  21  is formed by three or more layers including both N type and P type semiconductors stacked with one another in an interlacing manner, the type of the semiconductor material of an uppermost layer of the first epitaxial current-blocking layer  21  and the type of the semiconductor material of a lowermost layer of the first epitaxial current-blocking layer  21  are opposite to the type of the semiconductor material of the first semiconductor epitaxial layer  22 . That is, when the first semiconductor epitaxial layer  22  is a P type semiconductor, the uppermost layer and the lowermost layer of the first epitaxial current-blocking layer  21  are N type semiconductors; conversely, when the first semiconductor epitaxial layer  22  is an N type semiconductor, the uppermost layer and the lowermost layer of the first epitaxial current-blocking layer  21  are P type semiconductors. 
     In this embodiment, a heterojunction structure is formed on a junction interface between the first epitaxial current-blocking layer  21  and the first epitaxial semiconductor layer  22  to retard currents transmitting through the first epitaxial current-blocking layer  21  efficiently, so that currents are confined to pass only through the first current opening  211 . Because the first epitaxial current-blocking layer  21  is grown by the semiconductor epitaxy process, the surface emitting laser is not damaged during the manufacturing processes, and the structure of the laser structure layer  20  can be uniform and smooth. Hence, the junction interface between the metal bonding layer  11  and the epitaxial semiconductor reflection layer  12  and the laser structure layer  20  can be combined properly to improve the performance of the surface emitting laser efficiently. 
     Please refer to  FIG. 3 , illustrating a second embodiment of the instant disclosure. In the second embodiment, the structure of the metal bonding layer  11  is different from that of the first embodiment. In the second embodiment, the surface emitting laser further comprises an insulating layer  15 . A thickness of a portion of the metal bonding layer  11  corresponding to the first current opening  211  is retained, and the rest portions of the metal bonding layer  11  are etched downwardly by a depth via a semiconductor manufacturing process. The depth may be determined by the practical conditions of the manufacturing process. The maximized depth is about half of the thickness of the metal bonding layer  11 . The insulating layer  15  is on the surface of the etched portions of the metal bonding layer  11 , and the surface of the retained portions of the metal bonding layer  11  is flush with the surface of the insulating layer  15  and bonded to the first semiconductor epitaxial layer  22 . Hence, the currents can be gathered efficiently and prevented from being diffused. Moreover, the metal bonding layer  11  can be protected via the insulating layer  15 . 
     Please refer to  FIG. 4 , illustrating a third embodiment of the instant disclosure. In the third embodiment, the structure of the metal bonding layer  11  is different from that of the first embodiment. In the third embodiment, the surface emitting laser further comprises an insulating layer  15 A. A thickness of a portion of the metal bonding layer  11  corresponding to two sides of the first current opening  211  is retained, and rest portions of the metal bonding layer  11  are etched downwardly by a depth via a semiconductor manufacturing process. The depth may be determined by the practical conditions of the manufacturing process. The maximized depth is about half of the thickness of the metal bonding layer  11 . The insulating layer  15 A is on the surface of the etched portions of the metal bonding layer  11 , and the surface of the retained portions of the metal bonding layer  11  is flush with the surface of the insulating layer  15 A and bonded to the first semiconductor epitaxial layer  22 . Hence, the currents can be gathered efficiently and prevented from being diffused. Moreover, the metal bonding layer  11  can be protected via the insulating layer  15 A. 
     Please refer to  FIG. 5 , illustrating a fourth embodiment of the instant disclosure. In the fourth embodiment, the structure of the metal bonding layer  11  is different from that of the first embodiment. In the fourth embodiment, the surface emitting laser further comprises a conductive metal  16 . A portion of the metal bonding layer  11  corresponding to the first current opening  211  is etched to form a recessed groove  17  in a semiconductor manufacturing process. The conductive metal  16  is in the recessed groove  17  to correspond to the first current opening  211 . The surface of the conductive metal  16  is flush with the surface of the metal bonding layer  11  and bonded to the laser structure layer  20 . Hence, via the conductive metal  16 , the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 6 , illustrating a fifth embodiment of the instant disclosure. In the fifth embodiment, the structure of the metal bonding layer  11  is different from that of the first embodiment. In the fifth embodiment, the surface emitting laser further comprises two conductive metals  16 A. Portions of the metal bonding layer  11  respectively corresponding to the two sides of the first current opening  211  are etched downwardly to form two recessed grooves  17 A in a semiconductor manufacturing process. The conductive metals  16 A are in the recessed grooves  17 A, respectively. The surfaces of the conductive metals  16 A are flush with the surface of the metal bonding layer  11  and bonded to the laser structure layer  20 . Hence, via the conductive metals  16 A, the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 7 , illustrating a sixth embodiment of the instant disclosure. In the sixth embodiment, the surface emitting laser further comprises a transparent conductive layer  18  and a conductive metal  16 B. The transparent conductive layer  18  is between the metal bonding layer  11  and the laser structure layer  20 . A portion of the transparent conductive layer  18  corresponding to the first current opening  211  is etched to form a recessed groove  17 B in a semiconductor manufacturing process. The conductive metal  16 B is in the recessed groove  17 B. The surface of the conductive metal  16 B is flush with the surface of the transparent conductive layer  18  and bonded to the laser structure layer  20 . Hence, the mobility of the currents can be improved via the transparent conductive layer  18 , and via the conductive metal  16 B, the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 8 , illustrating a seventh embodiment of the instant disclosure. In the seventh embodiment, the surface emitting laser further comprises a transparent conductive layer  18 A and two conductive metals  16 C. The transparent conductive layer  18 A is between the metal bonding layer  11  and the laser structure layer  20 . Portions of the transparent conductive layer  18 A respectively corresponding to the two sides of the first current opening  211  are etched downwardly to form two recessed grooves  17 C. The conductive metals  16 C are in the recessed grooves  17 C, respectively. The surfaces of the conductive metals  16 C are flush with the surface of the transparent conductive layer  18 A and bonded to the laser structure layer  20 . Hence, the mobility of the currents can be improved via the transparent conductive layer  18 A, and via the conductive metals  16 C, the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 9 , illustrating an eighth embodiment of the instant disclosure. In the eighth embodiment, the surface emitting laser further comprises a transparent conductive layer  18 B, a conductive metal  16 D, and an insulating layer  15 B. The transparent conductive layer  18 B is between the metal bonding layer  11  and the laser structure layer  20 . The conductive metal  16 D is on a portion of the transparent conductive layer  18 B corresponding to the first current opening  211  and the conductive metal  16 D corresponds to the first current opening  211 . The insulating layer  15 B is on the surface of the transparent conductive layer  18 B and surrounds the conductive metal  16 D. The surface of the insulating layer  15 B is flush with the surface of the conductive metal  16 D and bonded to the laser structure layer  20 . Hence, via the conductive metal  16 D, the currents can be gathered efficiently and prevented from being diffused. Furthermore, the insulating layer  15 B can protect the transparent conductive layer  18 B. Moreover, the mobility of the currents can be improved via the transparent conductive layer  18 B. 
     Please refer to  FIG. 10 , illustrating a ninth embodiment of the instant disclosure. In the ninth embodiment, the surface emitting laser further comprises a transparent conductive layer  18 C, two conductive metals  16 E, and an insulating layer  15 C. The transparent conductive layer  18 C is between the metal bonding layer  11  and the laser structure layer  20 . The conductive metals  16 E are on portions of the transparent conductive layer  18 C corresponding to the two sides of the first current opening  211 , respectively. The insulating layer  15 C is on the surface of the transparent conductive layer  18 C and surrounds the conductive metals  16 E. The surface of the insulating layer  15 C is flush with the surfaces of the conductive metals  16 E and bonded to the laser structure layer  20 . Hence, via the conductive metals  16 E, the currents can be gathered efficiently and prevented from being diffused. Furthermore, the insulating layer  15 C can protect the transparent conductive layer  18 C and the insulating layer  15 C can prevent the currents from transmitting through other portions. Moreover, the mobility of the currents can be improved via the transparent conductive layer  18 C. 
     Please refer to  FIG. 11 , illustrating a tenth embodiment of the instant disclosure. In the tenth embodiment, the surface emitting laser further comprises a transparent conductive layer  18 D and a layer of conductive metal  16 F. The transparent conductive layer  18 D is between the metal bonding layer  11  and the laser structure layer  20 . The conductive metal  16 F is between the transparent conductive layer  18 D and the laser structure layer  20 . The conductive metal  16 F is a whole layer to correspond to the transparent conductive layer  18 D and the laser structure layer  20 . Hence, the mobility of the currents can be improved via the transparent conductive layer  18 D. Moreover, the layer of the conductive metal  16 F allows the currents to pass through the surface emitting laser evenly. 
     Please refer to  FIG. 12 , illustrating an eleventh embodiment of the instant disclosure. In the eleventh embodiment, the position of the first epitaxial current-blocking layer  21  is different from that of the first embodiment. In the eleventh embodiment, the first epitaxial current-blocking layer  21  is in the second semiconductor epitaxial layer  24 . When the first epitaxial current-blocking layer  21  is an N type semiconductor layer or a P type semiconductor layer, the type of the semiconductor material of the first epitaxial current-blocking layer  21  is opposite to the type of the semiconductor material of the second semiconductor epitaxial layer  24 . When the first epitaxial current-blocking layer  21  is formed by three of more layers including both N type and P type semiconductor layers stacked with one another in an interlacing manner, the type of the semiconductor material of an uppermost layer of the first epitaxial current-blocking layer  21  and the type of the semiconductor material of a lowermost layer of the first epitaxial current-blocking layer  21  are opposite to the type of the semiconductor material of the second semiconductor epitaxial layer  24 . 
     Please refer to  FIG. 13 , illustrating a twelfth embodiment of the instant disclosure. In the twelfth embodiment, the surface emitting laser further comprises an insulating layer  15 D. A thickness of a portion of the metal bonding layer  11  corresponding to the first current opening  211  is retained, and the rest portions of the metal bonding layer  11  are etched downwardly by a depth via a semiconductor manufacturing process. The depth may be determined by the practical conditions of the manufacturing process. The maximized depth is about half of the thickness of the metal bonding layer  11 . The insulating layer  15 D is on the surface of the etched portions of the metal bonding layer  11 , and the surface of the retained portions of the metal bonding layer  11  is flush with the surface of the insulating layer  15 D and bonded to the first semiconductor epitaxial layer  22 . Hence, the currents can be gathered efficiently and prevented from being diffused. Moreover, the metal bonding layer  11  can be protected via the insulating layer  15 . 
     Please refer to  FIG. 14 , illustrating a thirteenth embodiment of the instant disclosure. In the thirteenth embodiment, the surface emitting laser further comprises an insulating layer  15 E. A thickness of a portion of the metal bonding layer  11  corresponding to two sides of the first current opening  211  is retained, and rest portions of the metal bonding layer  11  are etched downwardly by a depth via a semiconductor manufacturing process. The depth may be determined by the practical conditions of the manufacturing process. The maximized depth is about half of the thickness of the metal bonding layer  11 . The insulating layer  15 E is on the surface of the etched portions of the metal bonding layer  11 , and the surface of the retained portions of the metal bonding layer  11  is flush with the surface of the insulating layer  15 E and bonded to the first semiconductor epitaxial layer  22 . Hence, the currents can be gathered efficiently and prevented from being diffused. Moreover, the metal bonding layer  11  can be protected via the insulating layer  15 E. 
     Please refer to  FIG. 15 , illustrating a fourteenth embodiment of the instant disclosure. In the fourteenth embodiment, the surface emitting laser further comprises a conductive metal  16 G A portion of the metal bonding layer  11  corresponding to the first current opening  211  is etched downwardly to form a recessed groove  17 D in a semiconductor manufacturing process. The conductive metal  16 G is in the recessed groove  17 D to correspond to the first current opening  211 . The surface of the conductive metal  16 G is flush with the surface of the metal bonding layer  11  and bonded to the laser structure layer  20 . Hence, via the conductive metal  16 G; the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 16 , illustrating a fifteenth embodiment of the instant disclosure. In the fifteenth embodiment, the surface emitting laser further comprises two conductive metals  16 H. Portions of the metal bonding layer  11  respectively corresponding to the two sides of the first current opening  211  are etched downwardly to form two recessed grooves  17 E in a semiconductor manufacturing process. The conductive metals  16 H are in the recessed grooves  17 E, respectively. The surfaces of the conductive metals  16 H are flush with the surface of the metal bonding layer  11  and bonded to the laser structure layer  20 . Hence, via the conductive metals  16 H, the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 17 , illustrating a sixteenth embodiment of the instant disclosure. In the sixteenth embodiment, the surface emitting laser further comprises a transparent conductive layer  18 E and a conductive metal  16 I. The transparent conductive layer  18 E is between the metal bonding layer  11  and the laser structure layer  20 . A portion of the transparent conductive layer  18 E corresponding to the first current opening  211  is etched to form a recessed groove  17 F in a semiconductor manufacturing process. The conductive metal  161  is in the recessed groove  17 F. The surface of the conductive metal  161  is flush with the surface of the transparent conductive layer  18 E and bonded to the laser structure layer  20 . Hence, the mobility of the currents can be improved via the transparent conductive layer  18 E, and via the conductive metal  16 I, the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 18 , illustrating a seventeenth embodiment of the instant disclosure. In the seventeenth embodiment, the surface emitting laser further comprises a transparent conductive layer  18 F and two conductive metals  16 J. The transparent conductive layer  18 F is between the metal bonding layer  11  and the laser structure layer  20 . Portions of the transparent conductive layer  18 F respectively corresponding to the two sides of the first current opening  211  are etched downwardly to form two recessed grooves  17 G. The conductive metals  16 J are in the recessed grooves  17 G respectively. The surfaces of the conductive metals  16 J are flush with the surface of the transparent conductive layer  18 F and bonded to the laser structure layer  20 . Hence, the mobility of the currents can be improved via the transparent conductive layer  18 F, and via the conductive metals  16 J, the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 19 , illustrating an eighteenth embodiment of the instant disclosure. In the eighteenth embodiment, the surface emitting laser further comprises a transparent conductive layer  18 G a conductive metal  16 K, and an insulating layer  15 F. The transparent conductive layer  18 G is between the metal bonding layer  11  and the laser structure layer  20 . The conductive metal  16 K is on a portion of the transparent conductive layer  18 G corresponding to the first current opening  211  and the conductive metal  16 K corresponds to the first current opening  211 . The insulating layer  15 F is on the surface of the transparent conductive layer  18 G and surrounds the conductive metal  16 K. The surface of the insulating layer  15 F is flush with the surface of the conductive metal  16 K and bonded to the laser structure layer  20 . Hence, the mobility of the currents can be improved via the transparent conductive layer  18 G. Moreover, via the conductive metal  16 K, the currents can be gathered efficiently and prevented from being diffused. Furthermore, the insulating layer  15 B can protect the transparent conductive layer  18 B and prevent the currents from transmitting through other portions. 
     Please refer to  FIG. 20 , illustrating a nineteenth embodiment of the instant disclosure. In the nineteenth embodiment, the surface emitting laser further comprises a transparent conductive layer  18 H, two conductive metals  16 L, and an insulating layer  15 G The transparent conductive layer  18 H is between the metal bonding layer  11  and the laser structure layer  20 . The conductive metals  16 L are on portions of the transparent conductive layer  18 H corresponding to the two sides of the first current opening  211 , respectively. The insulating layer  15 G is on the surface of the transparent conductive layer  18 H and surrounds the conductive metals  16 L. The surface of the insulating layer  15 G is flush with the surfaces of the conductive metals  16 L and bonded to the laser structure layer  20 . Hence, the mobility of the currents can be improved via the transparent conductive layer  18 H. Moreover, via the conductive metals  16 L, the currents can be gathered efficiently and prevented from being diffused. Furthermore, the insulating layer  15 G can protect the transparent conductive layer  18 H and prevent the currents from transmitting through other portions. 
     Please refer to  FIG. 21 , illustrating a twentieth embodiment of the instant disclosure. In the twentieth embodiment, the surface emitting laser further comprises a transparent conductive layer  18 I and a layer of conductive metal  16 M. The transparent conductive layer  18 I is between the metal bonding layer  11  and the laser structure layer  20 . The conductive metal  16 M is between the transparent conductive layer  18 I and the laser structure layer  20 . The conductive metal  16 M is a whole layer to correspond to the transparent conductive layer  18 I and the laser structure layer  20 . Hence, the mobility of the currents can be improved via the transparent conductive layer  18 I. Moreover, the layer of the conductive metal  16 M allows the currents to pass through the surface emitting laser evenly. 
     Please refer to  FIG. 22 , illustrating a twenty-first embodiment of the instant disclosure. In the twenty-first embodiment, the surface emitting laser further comprises a second epitaxial current-blocking layer  25 . The second epitaxial current-blocking layer  25  is in the second semiconductor epitaxial layer  24 . A middle portion of the second epitaxial current-blocking layer  25  has a second current opening  251  corresponding to the first current opening  211 , so that currents can be transmitted between the first electrode layer  13  and the metal bonding layer  11 . 
     In this embodiment, the second epitaxial current-blocking layer  25  and the first epitaxial current-blocking layer  21  are the same. When the second epitaxial current-blocking layer  25  is an N type semiconductor layer or a P type semiconductor layer, the type of the semiconductor material of the second epitaxial current-blocking layer  25  is opposite to the type of the semiconductor material of the second semiconductor epitaxial layer  24 . When the second epitaxial current-blocking layer  25  is formed by three or more layers including both N type and P type semiconductor layers stacked with one another in an interlacing manner, the type of the semiconductor material of an uppermost layer of the second epitaxial current-blocking layer  25  and the type of the semiconductor material of a lowermost layer of the second epitaxial current-blocking layer  25  are opposite to the type of the semiconductor material of the second semiconductor epitaxial layer  24 . 
     Please refer to  FIG. 23 , illustrating a twenty-second embodiment of the instant disclosure. In the twenty-second embodiment, the structure of the metal bonding layer  11  is different from that of the twenty-first embodiment. In the twenty-second embodiment, the surface emitting laser further comprises an insulating layer  15 H. A thickness of a portion of the metal bonding layer  11  corresponding to the first current opening  211  is retained, and the rest portions of the metal bonding layer  11  are etched downwardly by a depth via a semiconductor manufacturing process. The depth may be determined by the practical conditions of the manufacturing process. The maximized depth is about half of the thickness of the metal bonding layer  11 . The insulating layer  15 H is on the surface of the etched portions of the metal bonding layer  11 , and the surface of the retained portions of the metal bonding layer  11  is flush with the surface of the insulating layer  15 H and bonded to the first semiconductor epitaxial layer  22 . Hence, the currents can be gathered efficiently and prevented from being diffused. Moreover, the metal bonding layer  11  can be protected via the insulating layer  15 H. 
     Please refer to  FIG. 24 , illustrating a twenty-third embodiment of the instant disclosure. In the twenty-third embodiment, the structure of the metal bonding layer  11  is different from that of the twenty-first embodiment. In the twenty-third embodiment, the surface emitting laser further comprises an insulating layer  15 I. A thickness of a portion of the metal bonding layer  11  corresponding to two sides of the first current opening  211  is retained, and rest portions of the metal bonding layer  11  are etched downwardly by a depth via a semiconductor manufacturing process. The depth may be determined by the practical conditions of the manufacturing process. The maximized depth is about half of the thickness of the metal bonding layer  11 . The insulating layer  15 I is on the surface of the etched portions of the metal bonding layer  11 , and the surface of the retained portions of the metal bonding layer  11  is flush with the surface of the insulating layer  15 I and bonded to the first semiconductor epitaxial layer  22 . Hence, the currents can be gathered efficiently and prevented from being diffused. Moreover, the insulating layer  15 I can protect the metal bonding layer  11  and prevent the currents from transmitting through other portions. 
     Please refer to  FIG. 25 , illustrating a twenty-fourth embodiment of the instant disclosure. In the twenty-fourth embodiment, the structure of the metal bonding layer  11  is different from that of the twenty-first embodiment. In the twenty-fourth embodiment, the surface emitting laser further comprises a conductive metal  16 N. A portion of the metal bonding layer  11  corresponding to the first current opening  211  is etched to form a recessed groove  17 H in a semiconductor manufacturing process. The conductive metal  16 N is in the recessed groove  17 H to correspond to the first current opening  211 . The surface of the conductive metal  16 N is flush with the surface of the metal bonding layer  11  and bonded to the laser structure layer  20 . Hence, via the conductive metal  16 N, the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 26 , illustrating a twenty-fifth embodiment of the instant disclosure. In the twenty-fifth embodiment, the structure of the metal bonding layer  11  is different from that of the twenty-first embodiment. In the twenty-fifth embodiment, the surface emitting laser further comprises two conductive metals  16 O. Portions of the metal bonding layer  11  respectively corresponding to the two sides of the first current opening  211  are etched downwardly to form two recessed grooves  171  in a semiconductor manufacturing process. The conductive metals  16 O are in the recessed grooves  171 , respectively. The surfaces of the conductive metals  16 O are flush with the surface of the metal bonding layer  11  and bonded to the laser structure layer  20 . Hence, via the conductive metals  16 O, the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 27 , illustrating a twenty-sixth embodiment of the instant disclosure. In the twenty-sixth embodiment, the surface emitting laser further comprises a transparent conductive layer  18 J and a conductive metal  16 P. The transparent conductive layer  18 J is between the metal bonding layer  11  and the laser structure layer  20 . A portion of the transparent conductive layer  18 J corresponding to the first current opening  211  is etched to form a recessed groove  17 J in a semiconductor manufacturing process. The conductive metal  16 P is in the recessed groove  17 J. The surface of the conductive metal  16 P is flush with the surface of the transparent conductive layer  18 J and bonded to the laser structure layer  20 . Hence, via the conductive metal  16 P, the currents can be gathered efficiently and prevented from being diffused, and the mobility of the currents can be improved via the transparent conductive layer  18 J. 
     Please refer to  FIG. 28 , illustrating a twenty-seventh embodiment of the instant disclosure. In the twenty-seventh embodiment, the surface emitting laser further comprises a transparent conductive layer  18 K and two conductive metals  16 Q. The transparent conductive layer  18 K is between the metal bonding layer  11  and the laser structure layer  20 . Portions of the transparent conductive layer  18 K respectively corresponding to the two sides of the first current opening  211  are etched downwardly to form two recessed grooves  17 K. The conductive metals  16 Q are in the recessed grooves  17 K, respectively. The surfaces of the conductive metals  16 Q are flush with the surface of the transparent conductive layer  18 K and bonded to the laser structure layer  20 . Hence, via the conductive metals  16 Q, the currents can be gathered efficiently and prevented from being diffused, and the mobility of the currents can be improved via the transparent conductive layer  18 K. 
     Please refer to  FIG. 29 , illustrating a twenty-eighth embodiment of the instant disclosure. In the twenty-eighth embodiment, the surface emitting laser further comprises a transparent conductive layer  18 L, a conductive metal  16 R, and an insulating layer  15 J. The transparent conductive layer  18 L is between the metal bonding layer  11  and the laser structure layer  20 . The conductive metal  16 R is on a portion of the transparent conductive layer  18 L corresponding to the first current opening  211  and the conductive metal  16 R corresponds to the first current opening  211 . The insulating layer  15 J is on the surface of the transparent conductive layer  18 L and surrounds the conductive metal  16 R. The surface of the insulating layer  15 J is flush with the surface of the conductive metal  16 R and bonded to the laser structure layer  20 . Hence, via the conductive metal  16 R, the currents can be gathered efficiently and prevented from being diffused. Moreover, the mobility of the currents can be improved via the transparent conductive layer  18 L. Furthermore, the insulating layer  15 J can protect the transparent conductive layer  18 L and prevent the currents from transmitting through other portions. 
     Please refer to  FIG. 30 , illustrating a twenty-ninth embodiment of the instant disclosure. In the twenty-ninth embodiment, the surface emitting laser further comprises a transparent conductive layer  18 M, two conductive metals  16 S, and an insulating layer  15 K. The transparent conductive layer  18 M is between the metal bonding layer  11  and the laser structure layer  20 . The conductive metals  16 S are on portions of the transparent conductive layer  18 M corresponding to the two sides of the first current opening  211 , respectively. The insulating layer  15 K is on the surface of the transparent conductive layer  18 M and surrounds the conductive metals  16 S. The surface of the insulating layer  15 K is flush with the surfaces of the conductive metals  16 S and bonded to the laser structure layer  20 . Hence, via the conductive metals  16 S, the currents can be gathered efficiently and prevented from being diffused. Moreover, the mobility of the currents can be improved via the transparent conductive layer  18 M. Furthermore, the insulating layer  15 K can protect the transparent conductive layer  18 M and prevent the currents from transmitting through other portions. 
     Please refer to  FIG. 31 , illustrating a thirtieth embodiment of the instant disclosure. In the thirtieth embodiment, the surface emitting laser further comprises a transparent conductive layer  18 N and a layer of conductive metal  16 T. The transparent conductive layer  18 N is between the metal bonding layer  11  and the laser structure layer  20 . The conductive metal  16 T is between the transparent conductive layer  18 N and the laser structure layer  20 . The conductive metal  16 T is a whole layer to correspond to the transparent conductive layer  18 N and the laser structure layer  20 . Hence, the mobility of the currents can be improved via the transparent conductive layer  18 N. Moreover, the layer of the conductive metal  16 T allows the currents to pass through the surface emitting laser evenly. 
     In the foregoing embodiments, the insulating layers  15 - 15 K may be a titanium dioxide (TiO 2 ) transparent dielectric material, a silicon dioxide (SiO 2 ) transparent dielectric material, a silicon nitride (Si 3 N 4 ) transparent dielectric material, a magnesium fluoride (MgF 2 ) transparent dielectric material, or a transparent insulating polymer, etc. 
     In the foregoing embodiments, the transparent conductive layer  18 - 18 N may be made of indium tin oxide (ITO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), indium gallium zinc oxide (IGZO), beta-phase gallium oxide (β-Ga 2 O 3 ), etc. 
     Please refer to  FIG. 32 , illustrating a thirty-first embodiment. In this embodiment, the surface emitting laser comprises a conductive substrate  10 A, a first epitaxial semiconductor reflection layer  30 , a laser structure layer  20 A, a second epitaxial semiconductor reflection layer  40 , and a first electrode layer  13 A. The first epitaxial semiconductor reflection layer  30 , the laser structure layer  20 A, the second epitaxial semiconductor reflection layer  40 , and the first electrode layer  13 A form a surface-emitting type laser structure, and the surface-emitting type laser structure is manufactured by a semiconductor manufacturing process. 
     In this embodiment, the conductive substrate is an electrically conductive substrate with great heat dissipation and electrical conductive properties. The conductive substrate  10 A may be made of molybdenum, gallium phosphide, silicon, aluminum, or copper. 
     In this embodiment, the combination between the surface-emitting type laser structure and the conductive substrate  10 A may be accomplished by a wafer bonding process. In the wafer bonding process, a substrate for loading the surface-emitting type laser structure is removed, and then the surface-emitting type laser structure is transferred to an upper surface of the conductive substrate  10 A to form the surface emitting laser. In this embodiment, a second electrode layer  14 A is disposed on a lower surface of the conductive substrate  10 . 
     In this embodiment, the light generated by the laser structure layer  20 A is reflected between the first epitaxial semiconductor reflection layer  30  and the second epitaxial semiconductor reflection layer  40 , so that the light can be resonated back and forth to form resonance gain and emitted in the form of laser eventually. The first epitaxial semiconductor reflection layer  30  and the second epitaxial semiconductor reflection layer  40  may be formed by stacking two semiconductor materials with different reflection indexes to form distributed Bragg reflectors. The first electrode layer  13 A and the second electrode layer  14 A are for inputting voltage/current for testing and electrical connection in the subsequent packaging process. Moreover, the type of the semiconductor material of the second electrode layer  14 A is different from the type of the semiconductor material of the first electrode layer  13 A, and the first electrode layer  13 A and the second electrode layer  14 A have different electrical polarities. 
     The laser structure layer  20 A has a first epitaxial current-blocking layer  21 A, and a middle portion of the first epitaxial current-blocking layer  21 A has a first current opening  211 A, so that the currents only passes through the first current opening  211 . In this embodiment, the laser structure layer  20 A has a first semiconductor epitaxial layer  22 A, an emitting reaction active layer  23 A, and a second semiconductor epitaxial layer  24 A sequentially from the upper surface of the first epitaxial semiconductor reflection layer  30 . The type of the semiconductor material of the first semiconductor epitaxial layer  22 A is opposite to the type of the semiconductor material of the second semiconductor epitaxial layer  24 A. The first epitaxial current-blocking layer  21 A is in the first semiconductor epitaxial layer  22 A. 
     In this embodiment, the type of the semiconductor material of the first epitaxial semiconductor reflection layer  30  is opposite to the type of the semiconductor material of the second epitaxial semiconductor reflection layer  40 . The type of the semiconductor material of the first epitaxial semiconductor reflection layer  30  corresponds to the type of the semiconductor material of the first semiconductor epitaxial layer  22 A. The type of the semiconductor material of the second epitaxial semiconductor reflection layer  40  corresponds the type of the semiconductor material of the second semiconductor epitaxial layer  24 A. When the first semiconductor epitaxial layer  22 A is a P type semiconductor, the first epitaxial semiconductor reflection layer  30  is a P type semiconductor reflection layer, the second semiconductor epitaxial layer  24 A is an N type semiconductor, and the second epitaxial semiconductor reflection layer  40  is N type semiconductor reflection layer. Conversely, when the first semiconductor epitaxial layer  22 A is an N type semiconductor, the first epitaxial semiconductor reflection layer  30  is an N type semiconductor reflection layer, the second semiconductor epitaxial layer  24 A is a P type semiconductor, and the second epitaxial semiconductor reflection layer  40  is a P type semiconductor reflection layer. 
     Please refer to  FIGS. 2-1 and 2-2 . The first epitaxial current-blocking layer  21 A may be grown by a semiconductor epitaxy process. The first epitaxial current-blocking layer  21 A may be formed by an N type semiconductor layer or a P type semiconductor layer. Alternatively, the first epitaxial current-blocking layer  21 A may be formed by three of more layers including both N type and P type semiconductor layers. The N type and P type semiconductor layers are stacked with one another in an interlacing manner, and a total number of the stacked N type and P type semiconductor layers of the first epitaxial current-blocking layer  21 A is an odd number. 
     In this embodiment, the first epitaxial current-blocking layer  21 A may be an N type semiconductor layer or a P type semiconductor layer. The type of the semiconductor material of the first epitaxial current-blocking layer  21 A is opposite to the type of the semiconductor material of the first semiconductor epitaxial layer  22 A. That is, when the first semiconductor epitaxial layer  22 A is an N type semiconductor, the first epitaxial current-blocking layer  21 A is a P type semiconductor; conversely, when the first semiconductor epitaxial layer  22 A is a P type semiconductor, the first epitaxial current-blocking layer  21 A is an N type semiconductor. 
     In this embodiment, when the first epitaxial current-blocking layer  21 A is formed by three or more layers including both N type and P type semiconductors stacked with one another in an interlacing manner, the type of the semiconductor material of an uppermost layer of the first epitaxial current-blocking layer  21 A and the type of the semiconductor material of a lowermost layer of the first epitaxial current-blocking layer  21 A are opposite to the type of the semiconductor material of the first semiconductor epitaxial layer  22 A. That is, when the first semiconductor epitaxial layer  22 A is a P type semiconductor, the uppermost layer and the lowermost layer of the first epitaxial current-blocking layer  21 A are N type semiconductors; conversely, when the first semiconductor epitaxial layer  22 A is an N type semiconductor, the uppermost layer and the lowermost layer of the first epitaxial current-blocking layer  21 A are P type semiconductors. 
     Please refer to  FIG. 33 , illustrating a thirty-second embodiment of the instant disclosure. In the thirty-second embodiment, the surface emitting laser further comprises a metal bonding layer  11 A, and the metal bonding layer  11 A is disposed between the conductive substrate  10 A and the first epitaxial semiconductor reflection layer  30 . In this embodiment, the metal bonding layer  11 A is provided for bonding purposes, and the metal bonding layer  11 A may be further provided for electrical conduction. 
     Please refer to  FIG. 34 , illustrating a thirty-third embodiment of the instant disclosure. In the thirty-third embodiment, the structure of the metal bonding layer  11 A is different from that of the thirty-second embodiment. In the thirty-third embodiment, the surface emitting laser further comprises an insulating layer  50 . A thickness of a portion of the metal bonding layer  11 A corresponding to the first current opening  211 A is retained, and the rest portions of the metal bonding layer  11 A are etched downwardly by a depth via a semiconductor manufacturing process. The depth may be determined by the practical conditions of the manufacturing process, and the maximized depth is about half of the thickness of the metal bonding layer  11 A. The insulating layer  50  is on the surface of the etched portions of the metal bonding layer  11 A, and the surface of the retained portions of the metal bonding layer  11 A is flush with the surface of the insulating layer  50  and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, the retained portions of the metal bonding layer  11 A allow the currents to be efficiently gathered and prevent the currents from being diffused. Moreover, the etched portion of the metal bonding layer  11 A can be protected via the insulating layer  50 . 
     Please refer to  FIG. 35 , illustrating a thirty-fourth embodiment of the instant disclosure. In the thirty-fourth embodiment, the structure of the metal bonding layer  11 A is different from that of the thirty-second embodiment. In the thirty-fourth embodiment, the surface emitting laser further comprises an insulating layer  50 A. A thickness of a portion of the metal bonding layer  11 A corresponding to two sides of the first current opening  211 A is retained, and rest portions of the metal bonding layer  11 A are etched downwardly by a depth via a semiconductor manufacturing process. The depth may be determined by the practical conditions of the manufacturing process. The maximized depth is about half of the thickness of the metal bonding layer  11 A. The insulating layer  50 A is on the surface of the etched portions of the metal bonding layer  11 A, and the surface of the retained portions of the metal bonding layer  11 A is flush with the surface of the insulating layer  50 A and bonded to the first epitaxial reflection layer  30 . Hence, the retained portions of the metal bonding layer  11 A allow the currents to be efficiently gathered and prevent the currents from being diffused. Moreover, the insulating layer  50 A can protect the etched portion of the metal bonding layer  11 A and the insulating layer  50 A can prevent the currents from transmitting through other portions. 
     Please refer to  FIG. 36 , illustrating a thirty-fifth embodiment of the instant disclosure. In the thirty-fifth embodiment, the structure of the metal bonding layer  11 A is different from that of the thirty-second embodiment. In the thirty-fifth embodiment, the surface emitting laser further comprises a conductive metal  60 . A portion of the metal bonding layer  11 A corresponding to the first current opening  211 A is etched downwardly to form a recessed groove  70  in a semiconductor manufacturing process. The conductive metal  60  is in the recessed groove  70  to correspond to the first current opening  211 A. The surface of the conductive metal  60  is flush with the surface of the metal bonding layer  11 A and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, via the conductive metal  60 , the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 37 , illustrating a thirty-sixth embodiment of the instant disclosure. In the thirty-sixth embodiment, the structure of the metal bonding layer  11 A is different from that of the thirty-second embodiment. In the thirty-sixth embodiment, the surface emitting laser further comprises two conductive metals  60 A. Portions of the metal bonding layer  11 A respectively corresponding to the two sides of the first current opening  211 A are etched downwardly to form two recessed grooves  70 A in a semiconductor manufacturing process. The conductive metals  60 A are in the recessed grooves  70 A, respectively. The surfaces of the conductive metals  60 A are flush with the surface of the metal bonding layer  11 A and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, via the conductive metals  60 A, the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 38 , illustrating a thirty-seventh embodiment of the instant disclosure. In the thirty-seventh embodiment, the surface emitting laser further comprises a transparent conductive layer  80  and a conductive metal  60 B. The transparent conductive layer  80  is between the metal bonding layer  11 A and the first epitaxial semiconductor reflection layer  30 . A portion of the transparent conductive layer  80  corresponding to the first current opening  211 A is etched to form a recessed groove  70 B in a semiconductor manufacturing process. The conductive metal  60 B is in the recessed groove  70 B. The surface of the conductive metal  60 B is flush with the surface of the transparent conductive layer  80  and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, via the conductive metal  60 B, the currents can be gathered efficiently and prevented from being diffused, and the mobility of the currents can be improved via the transparent conductive layer  80 . 
     Please refer to  FIG. 39 , illustrating a thirty-eighth embodiment of the instant disclosure. In the thirty-eighth embodiment, the surface emitting laser further comprises a transparent conductive layer  80 A and two conductive metals  60 C. The transparent conductive layer  80 A is between the metal bonding layer  11 A and the first epitaxial semiconductor reflection layer  30 . Portions of the transparent conductive layer  80 A respectively corresponding to the two sides of the first current opening  211 A are etched downwardly to form two recessed grooves  70 C. The conductive metals  60 C are in the recessed grooves  70 C, respectively. The surfaces of the conductive metals  60 C are flush with the surface of the transparent conductive layer  80 A and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, via the conductive metals  60 C, the currents can be gathered efficiently and prevented from being diffused, and the mobility of the currents can be improved via the transparent conductive layer  80 A. 
     Please refer to  FIG. 40 , illustrating a thirty-ninth embodiment of the instant disclosure. In the thirty-ninth embodiment, the surface emitting laser further comprises a transparent conductive layer  80 B, a conductive metal  60 D, and an insulating layer  50 B. The transparent conductive layer  80 B is between the metal bonding layer  11 A and the first epitaxial semiconductor reflection layer  30 . The conductive metal  60 D is on a portion of the transparent conductive layer  80 B corresponding to the first current opening  211 A and the conductive metal  60 D corresponds to the first current opening  211 A. The insulating layer  50 B is on the surface of the transparent conductive layer  80 B and surrounds the conductive metal  60 D. The surface of the insulating layer  50 B is flush with the surface of the conductive metal  60 D and bonded to the first epitaxial semiconductor layer  30 . Hence, via the conductive metal  60 D, the currents can be gathered efficiently and prevented from being diffused. Moreover, the mobility of the currents can be improved via the transparent conductive layer  80 B. 
     Please refer to  FIG. 41 , illustrating a fortieth embodiment of the instant disclosure. In the fortieth embodiment, the surface emitting laser further comprises a transparent conductive layer  80 C, two conductive metals  60 E, and an insulating layer  50 C. The transparent conductive layer  80 C is between the metal bonding layer  11 A and the first epitaxial semiconductor layer  30 . The conductive metals  60 E are on portions of the transparent conductive layer  80 C corresponding to the two sides of the first current opening  211 A, respectively. The insulating layer  50 C is on the surface of the transparent conductive layer  80 C and surrounds the conductive metals  60 E. The surface of the insulating layer  50 C is flush with the surfaces of the conductive metals  60 E and bonded to the first epitaxial semiconductor layer  30 . Hence, via the conductive metals  60 E, the currents can be gathered efficiently and prevented from being diffused. Moreover, the mobility of the currents can be improved via the transparent conductive layer  80 C. Furthermore, the insulating layer  50 C can protect the transparent conductive layer  80 C and the insulating layer  50 C can prevent the currents from transmitting through other portions. 
     Please refer to  FIG. 42 , illustrating a forty-first embodiment of the instant disclosure. In the forty-first embodiment, the surface emitting laser further comprises a transparent conductive layer  80 D and a layer of conductive metal  60 F. The transparent conductive layer  80 D is between the metal bonding layer  11 A and the first epitaxial semiconductor reflection layer  30 . The conductive metal  60 F is between the transparent conductive layer  80 D and the first epitaxial semiconductor reflection layer  30 . The conductive metal  60 F is a whole layer to correspond to the transparent conductive layer  80 D and the first epitaxial semiconductor reflection layer  30 . Hence, the mobility of the currents can be improved via the transparent conductive layer  80 D. Moreover, the layer of the conductive metal  60 F allows the currents to pass through the surface emitting laser evenly. 
     Please refer to  FIG. 43 , illustrating a forty-second embodiment of the instant disclosure. In the forty-second embodiment, the position of the first epitaxial current-blocking layer  21 A is different from that of the thirty-first embodiment. In the forty-second embodiment, the first epitaxial current-blocking layer  21 A is in the second semiconductor epitaxial layer  24 A. When the first epitaxial current-blocking layer  21 A is an N type semiconductor layer or a P type semiconductor layer, the type of the semiconductor material of the first epitaxial current-blocking layer  21 A is opposite to the type of the semiconductor material of the second semiconductor epitaxial layer  24 A. When the first epitaxial current-blocking layer  21 A is formed by three of more layers including both N type and P type semiconductor layers stacked with one another in an interlacing manner, the type of the semiconductor material of an uppermost layer of the first epitaxial current-blocking layer  21 A and the type of the semiconductor material of a lowermost layer of the first epitaxial current-blocking layer  21 A are opposite to the type of the semiconductor material of the second semiconductor epitaxial layer  24 A. 
     Please refer to  FIG. 44 , illustrating a forty-third embodiment of the instant disclosure. In the forty-third embodiment, the surface emitting laser further comprises a metal bonding layer  11 B, and the metal bonding layer  11 B is disposed between the conductive substrate  10 A and the first epitaxial semiconductor reflection layer  30 . In this embodiment, the metal bonding layer  11 B is provided for bonding purposes, and the metal bonding layer  11 B may be further provided for electrical conduction. 
     Please refer to  FIG. 45 , illustrating a forty-fourth embodiment of the instant disclosure. In the forty-fourth embodiment, the structure of the metal bonding layer  11 B is different from that of the forty-third embodiment. In the forty-fourth embodiment, the surface emitting laser further comprises an insulating layer  50 D. A thickness of a portion of the metal bonding layer  11 B corresponding to the first current opening  211 A is retained, and the rest portions of the metal bonding layer  11 B are etched downwardly by a depth via a semiconductor manufacturing process. The depth may be determined by the practical conditions of the manufacturing process. The maximized depth is about half of the thickness of the metal bonding layer  11 B. The insulating layer  50 D is on the surface of the etched portions of the metal bonding layer  11 B, and the surface of the retained portions of the metal bonding layer  11 B is flush with the surface of the insulating layer  50 D and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, the retained portions of the metal bonding layer  11 B allow the currents to be efficiently gathered and prevent the currents from being diffused. Moreover, the etched portion of the metal bonding layer  11 A can be protected via the insulating layer  50 D. 
     Please refer to  FIG. 47 , illustrating a forty-fifth embodiment of the instant disclosure. In the forty-fifth embodiment, the structure of the metal bonding layer  11 B is different from that of the forty-third embodiment. In the forty-fifth embodiment, the surface emitting laser further comprises an insulating layer  50 E. A thickness of a portion of the metal bonding layer  11 B corresponding to two sides of the first current opening  211 A is retained, and rest portions of the metal bonding layer  11 B are etched downwardly by a depth via a semiconductor manufacturing process. The depth may be determined by the practical conditions of the manufacturing process. The maximized depth is about half of the thickness of the metal bonding layer  11 B. The insulating layer  50 E is on the surface of the etched portions of the metal bonding layer  11 B, and the surface of the retained portions of the metal bonding layer  11 B is flush with the surface of the insulating layer  50 E and bonded to the first epitaxial reflection layer  30 . Hence, the retained portions of the metal bonding layer  11 B allow the currents to be efficiently gathered and prevent the currents from being diffused. Moreover, the insulating layer  50 E can protect the etched portion of the metal bonding layer  11 B. 
     Please refer to  FIG. 47 , illustrating a forty-sixth embodiment of the instant disclosure. In the forty-sixth embodiment, the structure of the metal bonding layer  11 B is different from that of the forty-third embodiment. In the forty-sixth embodiment, the surface emitting laser further comprises a conductive metal  60 G A portion of the metal bonding layer  11 B corresponding to the first current opening  211 A is etched downwardly to form a recessed groove  70 D in a semiconductor manufacturing process. The conductive metal  60 G is in the recessed groove  70 D to correspond to the first current opening  211 A. The surface of the conductive metal  60 G is flush with the surface of the metal bonding layer  11 B and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, via the conductive metal  60 G; the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 48 , illustrating a forty-seventh embodiment of the instant disclosure. In the forty-seventh embodiment, the structure of the metal bonding layer  11 B is different from that of the forty-third embodiment. In the forty-seventh embodiment, the surface emitting laser further comprises two conductive metals  60 H. Portions of the metal bonding layer  11 B respectively corresponding to the two sides of the first current opening  211 A are etched downwardly to form two recessed grooves  70 E in a semiconductor manufacturing process. The conductive metals  60 H are in the recessed grooves  70 E, respectively. The surfaces of the conductive metals  60 H are flush with the surface of the metal bonding layer  11 B and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, via the conductive metals  60 H, the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 49 , illustrating a forty-eighth embodiment of the instant disclosure. In the forty-eighth embodiment, the surface emitting laser further comprises a transparent conductive layer  80 E and a conductive metal  601 . The transparent conductive layer  80 E is between the metal bonding layer  11 B and the first epitaxial semiconductor reflection layer  30 . A portion of the transparent conductive layer  80 E corresponding to the first current opening  211 A is etched to form a recessed groove  70 F in a semiconductor manufacturing process. The conductive metal  601  is in the recessed groove  70 F. The surface of the conductive metal  601  is flush with the surface of the transparent conductive layer  80 E and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, via the conductive metal  601 , the currents can be gathered efficiently and prevented from being diffused, and the mobility of the currents can be improved via the transparent conductive layer  80 . 
     Please refer to  FIG. 50 , illustrating a forty-ninth embodiment of the instant disclosure. In the forty-ninth embodiment, the surface emitting laser further comprises a transparent conductive layer  80 F and two conductive metals  60 J. The transparent conductive layer  80 F is between the metal bonding layer  11 B and the first epitaxial semiconductor reflection layer  30 . Portions of the transparent conductive layer  80 F respectively corresponding to the two sides of the first current opening  211 A are etched downwardly to form two recessed grooves  70 G. The conductive metals  60 J are in the recessed grooves  70 G respectively. The surfaces of the conductive metals  60 J are flush with the surface of the transparent conductive layer  80 F and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, via the conductive metals  60 J, the currents can be gathered efficiently and prevented from being diffused, and the mobility of the currents can be improved via the transparent conductive layer  80 F. 
     Please refer to  FIG. 51 , illustrating a fiftieth embodiment of the instant disclosure. In the fiftieth embodiment, the surface emitting laser further comprises a transparent conductive layer  80 G, a conductive metal  60 K, and an insulating layer  50 F. The transparent conductive layer  80 G is between the metal bonding layer  11 B and the first epitaxial semiconductor reflection layer  30 . The conductive metal  60 K is on a portion of the transparent conductive layer  80 G corresponding to the first current opening  211 A and the conductive metal  60 K corresponds to the first current opening  211 A. The insulating layer  50 F is on the surface of the transparent conductive layer  80 G and surrounds the conductive metal  60 K. The surface of the insulating layer  50 F is flush with the surface of the conductive metal  60 K and bonded to the first epitaxial semiconductor layer  30 . Hence, via the conductive metal  60 K, the currents can be gathered efficiently and prevented from being diffused. Moreover, the mobility of the currents can be improved via the transparent conductive layer  80 G. Furthermore, the insulating layer  50 F can protect the transparent conductive layer  80 G. 
     Please refer to  FIG. 52 , illustrating a fifty-first embodiment of the instant disclosure. In the fifty-first embodiment, the surface emitting laser further comprises a transparent conductive layer  80 H, two conductive metals  60 L, and an insulating layer  50 G The transparent conductive layer  80 H is between the metal bonding layer  11 L and the first epitaxial semiconductor layer  30 . The conductive metals  60 L are on portions of the transparent conductive layer  80 H corresponding to the two sides of the first current opening  211 A, respectively. The insulating layer  50 G is on the surface of the transparent conductive layer  80 H and surrounds the conductive metals  60 L. The surface of the insulating layer  50 G is flush with the surfaces of the conductive metals  60 L and bonded to the first epitaxial semiconductor layer  30 . Hence, via the conductive metals  60 L, the currents can be gathered efficiently and prevented from being diffused. Moreover, the mobility of the currents can be improved via the transparent conductive layer  80 H. Furthermore, the insulating layer  50 G can protect the transparent conductive layer  80 H. 
     Please refer to  FIG. 53 , illustrating a fifty-second embodiment of the instant disclosure. In the fifty-second embodiment, the surface emitting laser further comprises a transparent conductive layer  80 I and a layer of conductive metal  60 M. The transparent conductive layer  80 I is between the metal bonding layer  11 B and the first epitaxial semiconductor reflection layer  30 . The conductive metal  60 M is between the transparent conductive layer  80 I and the first epitaxial semiconductor reflection layer  30 . The conductive metal  60 M is a whole layer to correspond to the transparent conductive layer  80 I and the first epitaxial semiconductor reflection layer  30 . Hence, the mobility of the currents can be improved via the transparent conductive layer  80 I. Moreover, the layer of the conductive metal  60 M allows the currents to pass through the surface emitting laser evenly. 
     Please refer to  FIG. 52 , illustrating a fifty-third embodiment of the instant disclosure. In the fifty-third embodiment, the surface emitting laser further comprises a second epitaxial current-blocking layer  25 A. The second epitaxial current-blocking layer  25 A is in the second semiconductor epitaxial layer  24 A. A middle portion of the second epitaxial current-blocking layer  25 A has a second current opening  251 A corresponding to the first current opening  211 A. 
     In this embodiment, the second epitaxial current-blocking layer  25 A and the first epitaxial current-blocking layer  21 A are the same. When the second epitaxial current-blocking layer  25 A is an N type semiconductor layer or a P type semiconductor layer, the type of the semiconductor material of the second epitaxial current-blocking layer  25 A is opposite to the type of the semiconductor material of the second semiconductor epitaxial layer  24 A. When the second epitaxial current-blocking layer  25 A is formed by three or more layers including both N type and P type semiconductor layers stacked with one another in an interlacing manner, the type of the semiconductor material of an uppermost layer of the second epitaxial current-blocking layer  25 A and the type of the semiconductor material of a lowermost layer of the second epitaxial current-blocking layer  25 A are opposite to the type of the semiconductor material of the second semiconductor epitaxial layer  24 A. 
     Please refer to  FIG. 55 , illustrating a fifty-fourth embodiment of the instant disclosure. In the fifty-fourth embodiment, the surface emitting laser further comprises a metal bonding layer  11 C, and the metal bonding layer  11 C is disposed between the conductive substrate  10 A and the first epitaxial semiconductor reflection layer  30 . In this embodiment, the metal bonding layer  11 C is provided for bonding purposes, and the metal bonding layer  11 C may be further provided for electrical conduction. 
     Please refer to  FIG. 56 , illustrating a fifty-fifth embodiment of the instant disclosure. In the fifty-fifth embodiment, the structure of the metal bonding layer  11 C is different from that of the fifty-fourth embodiment. In the fifty-fifth embodiment, the surface emitting laser further comprises an insulating layer  50 H. A thickness of a portion of the metal bonding layer  11 C corresponding to the first current opening  211 A is retained, and the rest portions of the metal bonding layer  11 C are etched downwardly by a depth via a semiconductor manufacturing process. The depth may be determined by the practical conditions of the manufacturing process, and the maximized depth is about half of the thickness of the metal bonding layer  11 C. The insulating layer  50 H is on the surface of the etched portions of the metal bonding layer  11 C, and the surface of the retained portions of the metal bonding layer  11 C is flush with the surface of the insulating layer  50 H and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, the retained portions of the metal bonding layer  11 C allow the currents to be efficiently gathered and prevent the currents from being diffused. Moreover, the metal bonding layer  11 C can be protected via the insulating layer  50 H. 
     Please refer to  FIG. 57 , illustrating a fifty-sixth embodiment of the instant disclosure. In the fifty-sixth embodiment, the structure of the metal bonding layer  11 C is different from that of the fifty-fourth embodiment. In the fifty-sixth embodiment, the surface emitting laser further comprises an insulating layer  50 I. A thickness of a portion of the metal bonding layer  11 C corresponding to two sides of the first current opening  211 A is retained, and rest portions of the metal bonding layer  11 C are etched downwardly by a depth via a semiconductor manufacturing process. The depth may be determined by the practical conditions of the manufacturing process. The maximized depth is about half of the thickness of the metal bonding layer  11 C. The insulating layer  50 I is on the surface of the etched portions of the metal bonding layer  11 C, and the surface of the retained portions of the metal bonding layer  11 C is flush with the surface of the insulating layer  50 I and bonded to the first epitaxial reflection layer  30 . Hence, the retained portions of the metal bonding layer  11 C allow the currents to be efficiently gathered and prevent the currents from being diffused. Moreover, the insulating layer  50 I can protect the metal bonding layer  11 C. 
     Please refer to  FIG. 58 , illustrating a fifty-seventh embodiment of the instant disclosure. In the fifty-seventh embodiment, the structure of the metal bonding layer  11 C is different from that of the fifty-fourth embodiment. In the fifty-seventh embodiment, the surface emitting laser further comprises a conductive metal  60 N. A portion of the metal bonding layer  11 C corresponding to the first current opening  211 A is etched downwardly to form a recessed groove  70 H in a semiconductor manufacturing process. 
     The conductive metal  60 N is in the recessed groove  70 H to correspond to the first current opening  211 A. The surface of the conductive metal  60 N is flush with the surface of the metal bonding layer  11 C and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, via the conductive metal  60 N, the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 59 , illustrating a thirty-sixth embodiment of the instant disclosure. In the thirty-sixth embodiment, the structure of the metal bonding layer  11 C is different from that of the thirty-second embodiment. In the thirty-sixth embodiment, the surface emitting laser further comprises two conductive metals  60 O. Portions of the metal bonding layer  11 C respectively corresponding to the two sides of the first current opening  211 A are etched downwardly to form two recessed grooves  701  in a semiconductor manufacturing process. The conductive metals  60 O are in the recessed grooves  701 , respectively. The surfaces of the conductive metals  60 O are flush with the surface of the metal bonding layer  11 C and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, via the conductive metals  60 O, the currents can be gathered efficiently and prevented from being diffused. 
     Please refer to  FIG. 60 , illustrating a fifty-ninth embodiment of the instant disclosure. In the fifty-ninth embodiment, the surface emitting laser further comprises a transparent conductive layer  80 J and a conductive metal  60 P. The transparent conductive layer  80 J is between the metal bonding layer  11 C and the first epitaxial semiconductor reflection layer  30 . A portion of the transparent conductive layer  80 J corresponding to the first current opening  211 A is etched to form a recessed groove  70 J in a semiconductor manufacturing process. The conductive metal  60 P is in the recessed groove  70 J. The surface of the conductive metal  60 P is flush with the surface of the transparent conductive layer  80 J and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, via the conductive metal  60 P, the currents can be gathered efficiently and prevented from being diffused, and the mobility of the currents can be improved via the transparent conductive layer  80 J. 
     Please refer to  FIG. 61 , illustrating a sixtieth embodiment of the instant disclosure. In the sixtieth embodiment, the surface emitting laser further comprises a transparent conductive layer  80 K and two conductive metals  60 Q. The transparent conductive layer  80 K is between the metal bonding layer  11 C and the first epitaxial semiconductor reflection layer  30 . Portions of the transparent conductive layer  80 K respectively corresponding to the two sides of the first current opening  211 A are etched downwardly to form two recessed grooves  70 K. The conductive metals  60 Q are in the recessed grooves  70 K, respectively. The surfaces of the conductive metals  60 Q are flush with the surface of the transparent conductive layer  80 K and bonded to the first epitaxial semiconductor reflection layer  30 . Hence, via the conductive metals  60 Q, the currents can be gathered efficiently and prevented from being diffused, and the mobility of the currents can be improved via the transparent conductive layer  80 K. 
     Please refer to  FIG. 62 , illustrating a sixty-first embodiment of the instant disclosure. In the sixty-first embodiment, the surface emitting laser further comprises a transparent conductive layer  80 L, a conductive metal  60 R, and an insulating layer  50 J. The transparent conductive layer  80 L is between the metal bonding layer  11 C and the first epitaxial semiconductor reflection layer  30 . The conductive metal  60 R is on a portion of the transparent conductive layer  80 L corresponding to the first current opening  211 A and the conductive metal  60 R corresponds to the first current opening  211 A. The insulating layer  50 J is on the surface of the transparent conductive layer  80 L and surrounds the conductive metal  60 R. The surface of the insulating layer  50 J is flush with the surface of the conductive metal  60 R and bonded to the first epitaxial semiconductor layer  30 . Hence, via the conductive metal  60 R, the currents can be gathered efficiently and prevented from being diffused. Moreover, the mobility of the currents can be improved via the transparent conductive layer  80 L. Furthermore, the insulating layer  50 J can protect the transparent conductive layer  80 L and the insulating layer  50 J can prevent the currents from transmitting through other portions. 
     Please refer to  FIG. 63 , illustrating a sixty-second embodiment of the instant disclosure. In the sixty-second embodiment, the surface emitting laser further comprises a transparent conductive layer  80 M, two conductive metals  60 S, and an insulating layer  50 K. The transparent conductive layer  80 M is between the metal bonding layer  11 C and the first epitaxial semiconductor layer  30 . The conductive metals  60 S are on portions of the transparent conductive layer  80 M corresponding to the two sides of the first current opening  211 A, respectively. The insulating layer  50 K is on the surface of the transparent conductive layer  80 M and surrounds the conductive metals  60 S. The surface of the insulating layer  50 K is flush with the surfaces of the conductive metals  60 S and bonded to the first epitaxial semiconductor layer  30 . Hence, via the conductive metals  60 S, the currents can be gathered efficiently and prevented from being diffused. Moreover, the mobility of the currents can be improved via the transparent conductive layer  80 M. Furthermore, the insulating layer  50 K can protect the transparent conductive layer  80 M. 
     Please refer to  FIG. 64 , illustrating a sixty-third embodiment of the instant disclosure. In the sixty-third embodiment, the surface emitting laser further comprises a transparent conductive layer  80 N and a layer of conductive metal  60 T. The transparent conductive layer  80 N is between the metal bonding layer  11 C and the first epitaxial semiconductor reflection layer  30 . The conductive metal  60 T is between the transparent conductive layer  80 N and the first epitaxial semiconductor reflection layer  30 . The conductive metal  60 T is a whole layer to correspond to the transparent conductive layer  80 N and the first epitaxial semiconductor reflection layer  30 . Hence, the mobility of the currents can be improved via the transparent conductive layer  80 N. Moreover, the layer of the conductive metal  60 T allows the currents to pass through the surface emitting laser evenly. 
     In the foregoing embodiments, the insulating layers  50 - 50 K may be a titanium dioxide (TiO 2 ) transparent dielectric material, a silicon dioxide (SiO 2 ) transparent dielectric material, a silicon nitride (Si 3 N 4 ) transparent dielectric material, a magnesium fluoride (MgF 2 ) transparent dielectric material, or a transparent insulating polymer, etc. 
     In the foregoing embodiments, the transparent conductive layer  80 - 80 N may be made of indium tin oxide (ITO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), indium gallium zinc oxide (IGZO), beta-phase gallium oxide (β-Ga 2 O 3 ), etc. 
     The first current-blocking layer (i.e., the first epitaxial current-blocking layer  21 ,  21 A) and the second current-blocking layer (i.e., the second epitaxial current-blocking layer  25 ,  25 A) grown by the semiconductor epitaxy process allow the structure of the laser structure layer  20 ,  20 A to be smooth, so that the junction interface between the laser structure layer  20  and the epitaxial semiconductor reflection layer  12  (or the junction interfaces between the laser structure layer  20 A and the first epitaxial semiconductor reflection layer  30  and the second epitaxial semiconductor reflection layer  40 ) can be combined properly to improve the efficiency of the surface emitting laser.