Patent Publication Number: US-2021175687-A1

Title: Method of producing vertical cavity surface emitting laser, vertical cavity surface emitting laser, distance sensor, and electronic apparatus

Description:
TECHNICAL FIELD 
     The present technology relates to a method of producing a vertical cavity surface emitting laser that is a semiconductor laser device, the vertical cavity surface emitting laser, a distance sensor, and an electronic apparatus. 
     BACKGROUND ART 
     A vertical cavity surface emitting laser (VCSEL) device is a type of a semiconductor laser device, and is a device that resonates light in a direction orthogonal to a substrate surface and emits laser light in the same direction. 
     As a structure of the VCSEL device, for example, Non-Patent Literature 1 discloses a VCSEL device that includes a pair of DBRs (Distributed Bragg Reflectors) forming a resonator with a compound semiconductor light-emitting layer sandwiched therebetween. 
     One of the DBRs is formed by alternately stacking approximately 20 layers having different refractive indexes on a VCSEL device, the Al composition of AlGaAs having been changed between the layers. The other DBR is formed by alternately stacking approximately 20 layers of SiO 2  and Ta 2 O 5  on the silicon substrate side. 
     This VCSEL device is formed by bonding a compound semiconductor substrate on which the above-mentioned DBRs are formed and a silicon substrate with a BCB (benzene cyclobutene) resin. 
     CITATION LIST 
     Non-Patent Literature 
     Non-Patent Literature 1: Silicon-Integrated Hybrid-Cavity 850-nm VCSELs by Adhesive Bonding: Impact of Bonding Interface Thickness on Laser Performance, IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, VOL. 23, NO. 6, NOVEMBER/DECEMBER 2017 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     However, the VCSEL device described in the above-mentioned Non-Patent Literature 1 has large thermal resistances of the BCB resin and the DBR obtained by stacking SiO 2  and Ta 2 O. For this reason, the heat generated by laser emission is less likely to be emitted from the VCSEL device, and there is a possibility that the device characteristics are degraded by high temperatures. 
     In view of the circumstances as described above, it is an object of the present technology to provide a method of producing a vertical cavity surface emitting laser exhibiting excellent conductivity/heat-dissipation, the vertical cavity surface emitting laser, a distance sensor, and an electronic apparatus. 
     Solution to Problem 
     In order to achieve the above-mentioned object, a method of producing a vertical cavity surface emitting laser according to the present technology includes: creating a first substrate by sequentially stacking a dielectric DBR (Distributed Bragg Reflector) layer and a first dielectric to-be-bonded layer on a support substrate. 
     A second substrate is created by sequentially stacking a semiconductor DBR layer, a current blocking layer, an active layer, a contact layer, and a second dielectric to-be-bonded layer on a semiconductor substrate. 
     The dielectric to-be-bonded layers are bonded to each other. A bonded body of the first substrate and the second substrate are annealed. 
     In accordance with this production method, it is possible to bond the first substrate and the second substrate to each other via the dielectric layers (the first dielectric to-be-bonded layer and the second dielectric to-be-bonded layer) having large thermal conductivity, and improve the conductivity/heat-dissipation of the vertical cavity surface emitting laser. 
     The step of bonding the first dielectric to-be-bonded layer and the second dielectric to-be-bonded layer to each other may include performing plasma bonding in which the first dielectric to-be-bonded layer and the second dielectric to-be-bonded layer are irradiated with plasma and then the first dielectric to-be-bonded layer and the second dielectric to-be-bonded layer are bonded to each other. 
     The first dielectric to-be-bonded layer and the second dielectric to-be-bonded layer can be bonded to each other by plasma bonding. 
     The dielectric DBR layer may be configured by alternately stacking a first layer and a second layer, the first layer being formed of a first material, the second layer being formed of a second material, thermal conductivity of at least one of the first layer or the second layer being 10 W/mK or more. 
     By forming at least one of the first layer or the second layer constituting the dielectric DBR layer using a material having thermal conductivity of 10 W/mK or more, it is possible to reduce the thermal resistance of the dielectric DBR layer and further improve the conductivity/heat-dissipation of the vertical cavity surface emitting laser. 
     The dielectric DBR layer may be configured by alternately stacking a first layer and a second layer, the first layer being formed of a first material, the second layer being formed of a second material, a refractive index of at least one of the first layer or the second layer being 2 or more. 
     By forming at least one of the first layer or the second layer constituting the dielectric DBR layer using a material having a refractive index of 2 or more, it is possible to reduce the necessary thickness, reduce the thermal resistance of the dielectric DBR layer, and further improve the conductivity/heat-dissipation of the vertical cavity surface emitting laser. 
     The dielectric DBR layer may be configured by alternately stacking a first layer and a second layer, the first layer being formed of a first material, the second layer being formed of a second material, thermal conductivity of at least one of the first layer or the second layer being 10 W/mK or more, a refractive index of at least one of the first layer or the second layer being 2 or more. 
     The first dielectric to-be-bonded layer may be formed of any of SiO 2 , SiON, SiN, and Al 2 O 3 , and the second dielectric to-be-bonded layer may be formed of the same material as that of the first dielectric to-be-bonded layer. 
     The first material may be SiO 2 , and the second material may be Si 3 N 4 . 
     The first material may be Si 3 N 4 , and the second material may be TiO 2 . 
     The first material may be SiO 2 , and the second material may be Ta 2 O 5 . 
     The first material may be SiO 2 , and the second material may be TiO 2 . 
     In order to achieve the above-mentioned object, a vertical cavity surface emitting laser according to the present technology includes: an integrated body including a support substrate, a dielectric DBR layer, a dielectric to-be-bonded layer, a first contact layer, an active layer, a blocking layer, a semiconductor DBR layer, and a second contact layer. 
     The dielectric DBR layer is provided on the support substrate. 
     The dielectric to-be-bonded layer is provided on the dielectric DBR layer. 
     The first contact layer is provided on the dielectric to-be-bonded layer. 
     The active layer is provided on the first contact layer. 
     The blocking layer is provided on the active layer. 
     The semiconductor DBR layer is provided on the blocking layer. 
     The second contact layer is provided on the semiconductor DBR layer. 
     The dielectric DBR layer may be configured by alternately stacking a first layer and a second layer, the first layer being formed of a first material, the second layer being formed of a second material, thermal conductivity of at least one of the first layer or the second layer being 10 W/mK or more. 
     The dielectric DBR layer may be configured by alternately stacking a first layer and a second layer, the first layer being formed of a first material, the second layer being formed of a second material, a refractive index of at least one of the first layer or the second layer being 2 or more. 
     The dielectric DBR layer may be configured by alternately stacking a first layer and a second layer, the first layer being formed of a first material, the second layer being formed of a second material, thermal conductivity of at least one of the first layer or the second layer being 10 W/mK or more, a refractive index of at least one of the first layer or the second layer being 2 or more. 
     In order to achieve the above-mentioned object, a distance sensor according to the present technology includes a vertical cavity surface emitting laser. The vertical cavity surface emitting laser includes an integrated body including a support substrate, a dielectric DBR layer on the support substrate, a dielectric to-be-bonded layer on the dielectric DBR layer, a first contact layer on the dielectric to-be-bonded layer, an active layer on the first contact layer, a blocking layer on the active layer, a semiconductor DBR layer on the blocking layer, and a second contact layer on the semiconductor DBR layer. 
     In order to achieve the above-mentioned object, an electronic apparatus according to the present technology includes a vertical cavity surface emitting laser. 
     The vertical cavity surface emitting laser includes an integrated body including a support substrate, a dielectric DBR layer on the support substrate, a dielectric to-be-bonded layer on the dielectric DBR layer, a first contact layer on the dielectric to-be-bonded layer, an active layer on the first contact layer, a blocking layer on the active layer, a semiconductor DBR layer on the blocking layer, and a second contact layer on the semiconductor DBR layer. 
     Advantageous Effects of Invention 
     As described above, in accordance with the present technology, a method of producing a vertical cavity surface emitting laser exhibiting excellent conductivity/heat-dissipation, the vertical cavity surface emitting laser, a distance sensor, and an electronic apparatus are provided. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a cross-sectional view of a VCSEL device according to an embodiment of the present technology. 
         FIG. 2  is a cross-sectional view of a dielectric DBR layer of the VCSEL device. 
         FIG. 3  is a cross-sectional view of the VCSEL device to which a wiring is connected. 
         FIG. 4  is a table showing refractive indexes and thermal conductivity of respective materials. 
         FIG. 5  is a schematic diagram showing a stacked structure of a dielectric DBR layer of the VCSEL device. 
         FIG. 6  is a table showing materials of the dielectric DBR layer of the VCSEL device (having an emission wavelength of 840 nm), and the structure thereof. 
         FIG. 7  is a table showing materials of the dielectric DBR layer of the VCSEL device (having an emission wavelength of 940 nm), and the structure thereof. 
         FIG. 8  is a graph showing simulation results of the reflectance of the VCSEL device (having an emission wavelength of 840 nm). 
         FIG. 9  is a graph showing simulation results of the reflectance of the VCSEL device (having an emission wavelength of 940 nm). 
         FIG. 10  is a cross-sectional view of a first substrate used for producing the VCSEL device. 
         FIG. 11  is a cross-sectional view of a second substrate used for producing the VCSEL device. 
         FIG. 12  is a schematic diagram showing a method of producing the VCSEL device. 
         FIG. 13  is a schematic diagram showing the method of producing the VCSEL device. 
         FIG. 14  is a schematic diagram showing the method of producing the VCSEL device. 
         FIG. 15  is a schematic diagram showing the method of producing the VCSEL device. 
         FIG. 16  is a schematic diagram showing the method of producing the VCSEL device. 
         FIG. 17  is a schematic diagram showing the method of producing the VCSEL device. 
         FIG. 18  is a schematic diagram showing the method of producing the VCSEL device. 
         FIG. 19  is a schematic diagram showing the method of producing the VCSEL device. 
         FIG. 20  is a schematic diagram showing the method of producing the VCSEL device. 
         FIG. 21  is a schematic diagram showing the method of producing the VCSEL device. 
         FIG. 22  is a cross-sectional view of a VCSEL device integrated body according to an embodiment of the present technology. 
         FIG. 23  is a schematic diagram showing a method of producing the VCSEL device integrated body. 
         FIG. 24  is a schematic diagram showing the method of producing the VCSEL device integrated body. 
         FIG. 25  is a schematic diagram showing the method of producing the VCSEL device integrated body. 
     
    
    
     MODE(S) FOR CARRYING OUT THE INVENTION 
     A vertical cavity surface emitting laser (VCSEL) device according to an embodiment of the present technology will be described. 
     [Structure of VCSEL Device] 
       FIG. 1  is a cross-sectional view of a VCSEL device  100  according to this embodiment. As shown in the figure, the VCSEL device  100  is configured by stacking a support substrate  101 , a dielectric DBR layer  102 , a dielectric to-be-bonded layer  103 , a first contact layer  104 , an active layer  105 , a blocking layer  106 , a semiconductor DBR layer  107 , and a second contact layer  108  in this order. 
     The support substrate  101  supports the respective layers of the VCSEL device  100 . The support substrate  101  is formed of, for example, Si, Ge, or Al 2 O 3 . 
     The dielectric DBR layer  102  is a DBR (Distributed Bragg Reflector) formed of a dielectric.  FIG. 2  is a cross-sectional view showing the dielectric DBR layer  102 . As shown in the figure, the dielectric DBR layer  102  is configured by alternately stacking a first layer  102   a  and a second layer  102   b . The number of layers of the first layer  102   a  and the second layer  102   b  are not limited to the illustrated one. The thickness of the dielectric DBR layer  102  is, for example, 3 μm. The material of the first layer  102   a  and details of the second layer  102   b  will be described below. 
     The dielectric to-be-bonded layer  103  bonds the lower layer structure and the upper layer structure of the dielectric to-be-bonded layer  103 . The dielectric to-be-bonded layer  103  is formed of a dielectric, e.g., SiO 2 , SiON, SiN, or Al 2 O 3 . 
     The first contact layer  104  is formed of an n-type semiconductor material such as n-type GaAs. The thickness of the first contact layer  104  is, for example, 1 to 2 μm. 
     The active layer  105  is formed by alternately stacking a quantum well layer and a barrier layer, and forms a quantum well, the quantum well layer being formed of GaAs or the like and having a small band gap, the barrier layer being formed of AlGaAs or the like and having a large band gap. The thickness of the active layer  105  is, for example, 0.3 μm. 
     The blocking layer  106  includes an oxidized area  106   a  and a non-oxidized area  106   b , and applies a blocking effect to a current flowing between the first contact layer  104  and the second contact layer  108 . 
     The oxidized area  106   a  is formed of oxidized AlGaAs or the like, has low conductivity and a small refractive index, and functions as a light confinement area. The non-oxidized area  106   b  is formed of non-oxidized AlGaAs or the like, has higher conductivity than the oxidized area  106   a , and functions as a current injection area. The thickness of the blocking layer  106  is, for example, 0.15 μm. 
     The semiconductor DBR layer  107  is a DBR formed of a semiconductor. The semiconductor DBR layer  107  configured by alternately stacking a first layer and a second layer having different refractive indexes. The first layer is formed of, for example, Al x Ga 1-x As, and the second layer is formed of, for example, Al x Ga 1-x As having a composition different from that of the first layer. The number of stacked layers of the first layer and the second layer is not particularly limited. The thickness of the semiconductor DBR layer  107  is, for example, 3 μm. 
     The second contact layer  108  is formed of a p-type semiconductor material such as a p-type GaAs. The thickness of the second contact layer  108  is not particularly limited. However, since laser is transmitted through the second contact layer  108 , it is favorable that the thickness of the second contact layer  108  is smaller. 
       FIG. 3  is a cross-sectional view of the VCSEL device  100  to which a wiring is connected. As shown in the figure, an electrode  109  is formed on each of the first contact layer  104  and the second contact layer  108 . The surface of the VCSEL device  100  is covered with an insulation layer  110  formed of an insulation material. A pad  111  is formed on the insulation layer  110 , and the electrode  109  and the pad  111  are connected to each other via a wiring  112 . 
     [Operation of VCSEL Device] 
     The VCSEL device  100  operates in a way similar to that of a general VCSEL device. That is, when a voltage is applied between the first contact layer  104  and the second contact layer  108 , a current flows between the first contact layer  104  and the second contact layer  108 . 
     The current is subject to the blocking effect by the blocking layer  106 , and injected into the non-oxidized area  106   b . Due to this injected current, spontaneous emission light is generated in an area of the active layer  105  close to the non-oxidized area  106   b . The spontaneous emission light travels in the stacking direction of the VCSEL device  100  (direction orthogonal to the layers), and is reflected by the dielectric DBR layer  102  and the semiconductor DBR layer  107 . 
     The dielectric DBR layer  102  and the semiconductor DBR layer  107  are configured to reflect light having a specific wavelength (hereinafter, oscillation wavelength). The component of the spontaneous emission light having an oscillation wavelength forms a standing wave between the dielectric DBR layer  102  and the semiconductor DBR layer  107 , and is amplified by the active layer  105 . In the case where the injected current exceeds a threshold value, the light forming a standing wave performs laser oscillation, and is transmitted through the second contact layer  108  to be emitted. 
     [Regarding Material of Dielectric DBR Layer] 
     As described above, the dielectric DBR layer  102  is configured by alternately stacking the first layer  102   a  and the second layer  102   b . Hereinafter, the material of the first layer  102   a  will be referred to as the first material and the material of the second layer  102   b  will be referred to as the second material. 
     It is favorable that the thermal conductivity of at least one of the first material or the second material is 10 W/mK or more. Further, it is favorable that the refractive index of at least one of the first material or the second material is 2 or more. Further, it is more favorable that the thermal conductivity of at least one of the first material or the second material is 10 W/mK or more and the refractive index of at least one of the first material or the second material is 2 or more. 
       FIG. 4  is a table showing the refractive indexes and thermal conductivity of respective materials. Examples of the material having thermal conductivity of 10 W/mK or more include Si 3 N 4 , AlN, and TiO 2 . Further, examples of the material having a refractive index of 2 or more include Ta 2 O 5 , TiO 2 , AlN, Si, and GaAs. 
     When the combination of the first material and the second material is described as “the first material/the second material”, SiO 2 /Ta 2 O 5 , SiO 2 /Si 3 N 4 , SiO 2 /TiO 2 , or Si 3 N 4 /TiO 2  is favorable. 
       FIG. 5  is a schematic diagram showing a stacked structure of the dielectric DBR layer  102 . As shown in the figure, each of the first layer  102   a  and the second layer  102   b  has a thickness corresponding to λ/4. A represents the emission wavelength of the VCSEL device  100 , the thickness corresponding to λ/4 is determined by the refractive index of the corresponding material. A pair of one first layer  102   a  and one second layer  102   b  will be referred to as the stacked layer pair. 
       FIG. 6  and  FIG. 7  are each a table showing the thickness corresponding to λ/4 for the combination of the first material/the second material, the reflectance, and the thermal resistance.  FIG. 6  is a table in the case where an emission wavelength A of the VCSEL device  100  is 840 nm, and  FIG. 7  is a table in the case where the emission wavelength A of the VCSEL device  100  is 940 nm. 
       FIG. 8  shows simulation results of the reflectance of the VCSEL device  100  having the emission wavelength A of 840 nm, and  FIG. 9  shows simulation results of the reflectance of the VCSEL device  100  having the emission wavelength A of 940 nm. 
     As shown in  FIG. 6 , in the case of SiO 2 /Ta 2 O 5 , the thickness corresponding to λ/4 of SiO 2  is 144 nm and the thickness corresponding to λ/4 of Ta 2 O 5  is 117 nm. In order to achieve the reflectance of 99.96%, it is necessary to make the number of the stacked layer pairs  20 . In this case, the thermal resistance is 4.7×10 −6  m 2 ·K/W, and the thermal resistance of the dielectric DBR layer  102  can be reduced. 
     Also in the cases of SiO 2 /Si 3 N 4 , SiO 2 /TiO 2 , and Si 3 N 4 /TiO 2 , the thermal resistance of the dielectric DBR layer  102  can be reduced as shown in  FIG. 6  and  FIG. 7 , and thus, they are favorable as the first material and the second material. 
     Note that the dielectric DBR layer  102  is not limited to the one obtained by alternately stacking two types of materials, and may be one obtained by alternately stacking three or more types of materials. 
     Even in this case, it is favorable that the thermal conductivity of at least one of a plurality of materials forming the dielectric DBR layer  102  is 10 W/mK or more. Further, it is favorable that the refractive index of at least one of the plurality of materials is 2 or more. Further, it is more favorable that the thermal conductivity of at least one of the plurality of materials is 10 W/mK or more and the refractive index of at least one of the plurality of materials is 2 or more. 
     [Method of Producing VCSEL Device] 
     A method of producing the VCSEL device  100  will be described. The VCSEL device  100  can be produced by preparing the first substrate and the second substrate, and bonding them to each other. Note that in the following description, layers to be the respective layers of the above-mentioned VCSEL device  100  will be denoted by the same reference symbols as those of the respective layers of the VCSEL device  100 . 
       FIG. 10  is a cross-sectional view showing a first substrate  210 . As shown in the figure, the first substrate  210  is formed by sequentially stacking the support substrate  101 , the dielectric DBR layer  102 , and a first dielectric to-be-bonded layer  211 . 
     The dielectric DBR layer  102  can be formed by alternately depositing the first layer  102   a  and the second layer  102   b  on the support substrate  101 . The deposition of the first layer  102   a  and the second layer  102   b  can be performed by a sputtering method, a CVD (chemical vapor deposition) method, or an ALD (Atomic Layer Deposition) method. 
     The first dielectric to-be-bonded layer  211  is a layer formed of the same material as that of the above-mentioned dielectric to-be-bonded layer  103 . The first dielectric to-be-bonded layer  211  can be stacked on the dielectric DBR layer  102  by a sputtering method, a CVD method, or an ALD method. 
       FIG. 11  is a cross-sectional view showing a second substrate  220 . As shown in the figure, the second substrate  220  is formed by sequentially stacking a semiconductor substrate  221 , the second contact layer  108 , the semiconductor DBR layer  107 , the blocking layer  106 , the active layer  105 , the first contact layer  104 , and a second dielectric to-be-bonded layer  222 . 
     The second contact layer  108 , the semiconductor DBR layer  107 , the blocking layer  106 , the active layer  105 , and the first contact layer  104  can be stacked on the semiconductor substrate  221  by epitaxial growth by an MOCVD (metal organic chemical vapor deposition) method. 
     The second dielectric to-be-bonded layer  222  is a layer formed of the same material as that of the above-mentioned dielectric to-be-bonded layer  103 . The second dielectric to-be-bonded layer  222  can be stacked on the first contact layer  104  by a sputtering method, a CVD method, or an ALD method. 
       FIG. 12  to  FIG. 21  are each a schematic diagram showing the production process of the VCSEL device  100 . As shown in  FIG. 12 , the first dielectric to-be-bonded layer  211  and the second dielectric to-be-bonded layer  222  are flattened at an atomic level. This flattening can be performed by CMP (chemical mechanical polishing). 
     At this time, in order to achieve a high yield as the VCSEL device  100 , it is necessary for the active layer  105  to have an “antinode” of optical resonance, and the thickness variation of the first dielectric to-be-bonded layer  211  and the second dielectric to-be-bonded layer  222  needs to be approximately 50 nm or less. For this reason, it is better to precisely control the flattening while measuring the entire thickness of the first substrate  220  and the second substrate  220 . 
     Subsequently, the first dielectric to-be-bonded layer  211  and the second dielectric to-be-bonded layer  222  are irradiated with plasma. By the plasma irradiation, dangling bonds are formed in the first dielectric to-be-bonded layer  211  and the second dielectric to-be-bonded layer  222 . Further, as shown in  FIG. 13 , the first substrate  210  and the second substrate  220  are caused to face each other so that the first dielectric to-be-bonded layer  211  and the second dielectric to-be-bonded layer  222  are adjacent to each other, and thus, the first substrate  210  and the second substrate  220  are brought into contact with each other as shown in  FIG. 14 . 
     As a result, as shown in  FIG. 15 , the first dielectric to-be-bonded layer  211  and the second dielectric to-be-bonded layer  222  are boded to each other (normal-temperature plasma bonding) to form the dielectric to-be-bonded layer  103 . In this way, a bonded body  230  of the first substrate  210  and the second substrate  220  is formed. 
     Subsequently, the bonded body  230  is annealed to strengthen the bonding between the first dielectric to-be-bonded layer  211  and the second dielectric to-be-bonded layer  222 . Specifically, by this annealing, the dangling bonds formed by the above-mentioned plasma irradiation form bonding. 
     Subsequently, the semiconductor substrate  221  is thinned and removed, leaving the second contact layer  108  as shown in  FIG. 16 . Further, as shown in  FIG. 17 , a part of each of the second contact layer  108 , the semiconductor DBR layer  107 , the blocking layer  106 , the active layer  105 , and the first contact layer  104  is removed to form a mesa post shape. 
     Subsequently, as shown in  FIG. 18 , oxidation treatment is performed on a part of the blocking layer  106  to form the oxidized area  106   a  and the non-oxidized area  106   b.    
     Subsequently, as shown in  FIG. 19 , the electrode  109  is formed on each of the first contact layer  104  and the second contact layer  108 . Further, the insulation layer  110 , the pad  111 , and the wiring  112  are formed (see  FIG. 3 ). 
     The VCSEL device  100  can be produced in this way. Note that although the second contact layer  108  is formed on the semiconductor substrate  221  in the above description, the second contact layer  108  may be formed after bonding. 
     In this case, as shown in  FIG. 20 , the one obtained by directly stacking the semiconductor DBR layer  107  on the semiconductor substrate  221  is used as the second substrate  220 , and the semiconductor substrate  221  is thinned as shown in  FIG. 21 . Further, the thinned semiconductor substrate  221  can be doped with impurities to obtain the second contact layer  108  shown in  FIG. 16 . 
     [Regarding Effect by VCSEL Device] 
     The VCSEL device  100  has the configuration described above. As described above, the VCSEL device  100  is formed by bonding the first substrate  210  and the second substrate  220  via the dielectric to-be-bonded layer  103 . The dielectric to-be-bonded layer  103  is formed of a dielectric material having high thermal conductivity such as SiO 2 , and capable of increasing the conductivity/heat-dissipation of the VCSEL device  100 . 
     Further, by using the above-mentioned materials as the materials (the first material and the second material) of the dielectric DBR layer  102 , it is possible to reduce the thermal resistance of the dielectric DBR layer  102  and improve the conductivity/heat-dissipation of the VCSEL device  100 . 
     The VCSEL device  100  can be used as a light-emitting device of a distance sensor used for face recognition or the like in various electronic apparatuses such as a smartphone. 
     [Regarding VCSEL Integrated Body] 
     The VCSEL device  100  can be used as an integrated body.  FIG. 22  is a cross-sectional view of a VCSEL integrated body  300  that is an integrated body of VCSEL devices. 
     As shown in the figure, the VCSEL integrated body  300  includes a plurality of VCSEL devices  310 . Each of the VCSEL devices  310  includes the same layer structure as that of the VCSEL device  100 , and the support substrate  101 , the dielectric DBR layer  102 , and the dielectric to-be-bonded layer  103  are common to the plurality of VCSEL devices  310 . 
     The number and arrangement of the VCSEL devices  310  are not particularly limited, and the VCSEL devices  310  may be arranged in a one-dimensional array or a two-dimensional array. By integrating the VCSEL devices  310 , it is possible to form high-power laser. 
     [Regarding Method of Producing VCSEL Integrated Body] 
     The method of producing the VCSEL integrated body  300  will be described. The VCSEL integrated body  300  can be produced by a production process similar to that of the VCSEL device  100 . That is, the first substrate  210  and the second substrate  220  are bonded to each other (see  FIG. 10  to  FIG. 15 ), the semiconductor substrate  221  is thinned (see  FIG. 16 ), and then, a mesa post shape is formed (see  FIG. 17 ). 
     At this time, by forming a plurality of mesa posts separated from each other and forming the oxidized area  106   a  and the non-oxidized area  106   b  (see  FIG. 18 ), the respective mesa posts are obtained as the VCSEL devices  310 . It is possible to produce the VCSEL integrated body  300  including a plurality of VCSEL devices  310  from the bonded body  230  in which one first substrate  210  and one second substrate  220  are bonded to each other. 
       FIG. 23  to  FIG. 25  are each a schematic diagram showing the method of forming a wiring and an embedding film of the VCSEL integrated body  300 . As shown in  FIG. 23 , an embedding film  321  is formed on the VCSEL integrated body  300 . The embedding film  321  can be, for example, SiO 2 , and can be deposited by CVD or the like. 
     Further, the embedding film  321  may be formed of inorganic water glass by SOG (Spin on Glass) or the like, or may be formed by spin-coating an organic polymer such as BCB (benzene cyclobutene) and polyimide. The thickness of the embedding film  321  is favorably approximately 1.5 times the height of the VCSEL devices  310  (height from the dielectric to-be-bonded layer  103  to the second contact layer  108 ). 
     Subsequently, as shown in  FIG. 24 , the embedding film  321  is flattened. The flattening can be performed by, for example, CMP. Subsequently, contact holes are formed in the embedding film  321 , and electrodes  322  and wirings  323  are formed as shown in  FIG. 25 . In this way, the wiring and the embedding film can be formed in the VCSEL integrated body  300 . 
     Since the embedding film  321  flattens the surface of the VCSEL integrated body  300  and makes it easy to form the wirings  323 , it is possible to improve the wiring yield. 
     [Regarding Optoelectronic Integrated Circuit] 
     By providing a diffraction grating on the dielectric DBR layer  102 , an optoelectronic integrated circuit can be configured by the VCSEL device  100 . In this case, after forming the dielectric DBR layer  102  in the first substrate  210  (see  FIG. 10 ), it only needs to form a diffraction grating on the dielectric DBR layer  102  and provide the first dielectric to-be-bonded layer  211  thereon. The laser generated in the VCSEL device  100  is guided into the optical integrated circuit by this diffraction grating. 
     It should be noted that the present technology may take the following configurations. 
     (1) 
     A method of producing a vertical cavity surface emitting laser, including: 
     creating a first substrate by sequentially stacking a dielectric DBR (Distributed Bragg Reflector) layer and a first dielectric to-be-bonded layer on a support substrate; 
     creating a second substrate by sequentially stacking a semiconductor DBR layer, a current blocking layer, an active layer, a contact layer, and a second dielectric to-be-bonded layer on a semiconductor substrate; 
     bonding the first dielectric to-be-bonded layer and the second dielectric to-be-bonded layer to each other; and 
     annealing a bonded body of the first substrate and the second substrate. 
     (2) 
     The method of producing a vertical cavity surface emitting laser according to (1) above, in which 
     the step of bonding the first dielectric to-be-bonded layer and the second dielectric to-be-bonded layer to each other includes performing plasma bonding in which the first dielectric to-be-bonded layer and the second dielectric to-be-bonded layer are irradiated with plasma and then the first dielectric to-be-bonded layer and the second dielectric to-be-bonded layer are bonded to each other. 
     (3) 
     The method of producing a vertical cavity surface emitting laser according to (1) or (2) above, in which 
     the dielectric DBR layer is configured by alternately stacking a first layer and a second layer, the first layer being formed of a first material, the second layer being formed of a second material, thermal conductivity of at least one of the first layer or the second layer being 10 W/mK or more. 
     (4) 
     The method of producing a vertical cavity surface emitting laser according to (1) or (2) above, in which 
     the dielectric DBR layer is configured by alternately stacking a first layer and a second layer, the first layer being formed of a first material, the second layer being formed of a second material, a refractive index of at least one of the first layer or the second layer being 2 or more. 
     (5) 
     The method of producing a vertical cavity surface emitting laser according to (1) or (2) above, in which 
     the dielectric DBR layer is configured by alternately stacking a first layer and a second layer, the first layer being formed of a first material, the second layer being formed of a second material, thermal conductivity of at least one of the first layer or the second layer being 10 W/mK or more, a refractive index of at least one of the first layer or the second layer being 2 or more. 
     (6) 
     The method of producing a vertical cavity surface emitting laser according to any one of (1) to (5) above, in which 
     the first dielectric to-be-bonded layer is formed of any of SiO 2 , SiON, SiN, and Al 2 O 3 , and 
     the second dielectric to-be-bonded layer is formed of the same material as that of the first dielectric to-be-bonded layer. 
     (7) 
     The method of producing a vertical cavity surface emitting laser according to any one of (1) to (6) above, in which 
     the first material is SiO 2 , and 
     the second material is Si 3 N 4 . 
     (8) 
     The method of producing a vertical cavity surface emitting laser according to any one of (1) to (6) above, in which 
     the first material is Si 3 N 4 , and 
     the second material is TiO 2 . 
     (9) 
     The method of producing a vertical cavity surface emitting laser according to any one of (1) to (6) above, in which 
     the first material is SiO 2 , and 
     the second material is Ta 2 O 5 . 
     (10) 
     The method of producing a vertical cavity surface emitting laser according to any one of (1) to (6) above, in which 
     the first material is SiO 2 , and 
     the second material is TiO 2 . 
     (11) 
     A vertical cavity surface emitting laser, including 
     an integrated body including
         a support substrate,   a dielectric DBR layer on the support substrate,   a dielectric to-be-bonded layer on the dielectric DBR layer,   a first contact layer on the dielectric to-be-bonded layer,   an active layer on the first contact layer,   a blocking layer on the active layer,   a semiconductor DBR layer on the blocking layer, and   a second contact layer on the semiconductor DBR layer.       

     (12) 
     The vertical cavity surface emitting laser according to (11) above, in which 
     the dielectric DBR layer is configured by alternately stacking a first layer and a second layer, the first layer being formed of a first material, the second layer being formed of a second material, thermal conductivity of at least one of the first layer or the second layer being 10 W/mK or more. 
     (13) 
     The vertical cavity surface emitting laser according to (11) above, in which 
     the dielectric DBR layer is configured by alternately stacking a first layer and a second layer, the first layer being formed of a first material, the second layer being formed of a second material, a refractive index of at least one of the first layer or the second layer being 2 or more. 
     (14) 
     The vertical cavity surface emitting laser according to (11) above, in which 
     the dielectric DBR layer is configured by alternately stacking a first layer and a second layer, the first layer being formed of a first material, the second layer being formed of a second material, thermal conductivity of at least one of the first layer or the second layer being 10 W/mK or more, a refractive index of at least one of the first layer or the second layer being 2 or more. 
     (15) 
     A distance sensor, including 
     a vertical cavity surface emitting laser that includes an integrated body including 
     a support substrate, 
     a dielectric DBR layer on the support substrate, 
     a dielectric to-be-bonded layer on the dielectric DBR layer, 
     a first contact layer on the dielectric to-be-bonded layer, 
     an active layer on the first contact layer, 
     a blocking layer on the active layer, 
     a semiconductor DBR layer on the blocking layer, and 
     a second contact layer on the semiconductor DBR layer. 
     (16) 
     An electronic apparatus, including 
     a vertical cavity surface emitting laser that includes an integrated body including 
     a support substrate, 
     a dielectric DBR layer on the support substrate, 
     a dielectric to-be-bonded layer on the dielectric DBR layer, 
     a first contact layer on the dielectric to-be-bonded layer, 
     an active layer on the first contact layer, 
     a blocking layer on the active layer, 
     a semiconductor DBR layer on the blocking layer, and 
     a second contact layer on the semiconductor DBR layer. 
     REFERENCE SIGNS LIST 
     
         
         
           
               100  VCSEL device 
               101  support substrate 
               102  dielectric DBR layer 
               102   a  first layer 
               102   b  second layer 
               103  dielectric to-be-bonded layer 
               104  first contact layer 
               105  active layer 
               106  blocking layer 
               106   a  oxidized area 
               106   b  non-oxidized area 
               107  semiconductor DBR layer 
               108  second contact layer 
               210  first substrate 
               211  first dielectric to-be-bonded layer 
               220  second substrate 
               221  semiconductor substrate 
               222  second dielectric to-be-bonded layer 
               230  bonded body 
               300  VCSEL integrated body 
               310  VCSEL device