Abstract:
A method of manufacturing a thin-film thermo-electric generator includes the steps of: forming two or more PN junctions each having a three-layer structure; forming a substrate which has a first side and an opposed second side; coupling the PN junctions at the first side of the substrate to define a first group of PN junctions at the first side of the substrate; and providing two electrodes that one of the electrodes is extracted from the first group of PN junctions. Accordingly, each of the PN junctions is formed by depositing an insulating thin-film layer between a P-type thermo-electric thin-film layer and a N-type thermo-electric thin-film layer.

Description:
CROSS REFERENCE OF RELATED APPLICATION 
       [0001]    This is a Continuation application that claims priority to U.S. non-provisional application, application Ser. No. 13/126,076, filed Apr. 26, 2011, which claims priority to international application number PCT/CN2009/075419, international filing date Dec. 9, 2009. 
     
    
     NOTICE OF COPYRIGHT 
       [0002]    A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to any reproduction by anyone of the patent disclosure, as it appears in the United States Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. 
       BACKGROUND OF THE PRESENT INVENTION 
       [0003]    1. Field of Invention 
         [0004]    This invention relates to thermo-electric technology, and more particularly to a thin-film thermo-electric generator and fabrication method thereof. 
         [0005]    2. Description of Related Arts 
         [0006]    The thermo-electric generator is a kind of generator made on the basis of Seebeck Effect, the heat energy is transformed into electric energy. The working principle of thermo-electric generator is that connecting one end of two different metals or two different types of thermo-electric conversion materials P-type and N-type semiconductors, placing this end in high temperature condition, and placing the other end in low temperature condition. Compared with the other end, the end in high temperature condition has better thermal activation and higher density of electrons and holes, the electrons and holes spread to the end in low temperature condition, thus an electric potential difference is formed in the end in low temperature condition. Combing a number of this kind of thermo-electric conversion materials P-type and N-type semiconductors to form a module supplying adequate voltage, this module becomes a thermo-electric generator. 
         [0007]    The thermo-electric generator is a kind of clean, noiseless energy without discharging any hazardous substance, having high reliability and long useful time, and supplying long, safe, continuous and stable electricity output. Presently the thermo-electric generator is made by cutting and welding the thermo-electric materials. There are two types of fabrication methods. In the first method, depositing a photosensitive resist on the same chip, then forming a P-type and N-type area through double photo etching respectively, and finally depositing P-type and N-type thermo-electric materials in the P-type and N-type area respectively. This method is difficult for application, especially for the procedure of combining thermo-electric units in which the chip is required to be stripped from the deposited thermo-electric units. In the second method, P-type and N-type thermo-electric unit chip is separately manufactured, in the fabrication of micro thin-film thermo-electric generator, the conducting layer connecting P-type and N-type thermo-electric units can be manufactured on condition that the chip is not stripped from the deposited thermo-electric units. This method has complicated procedures, and the thin-film of the thermo-electric generator is merely limited to single thin-film, so the performance is limited. 
       SUMMARY OF THE PRESENT INVENTION 
       [0008]    To solve the above-mentioned problems, this invention provides a thin-film thermo-electric generator and fabrication method thereof, improving the performance and simplifying the fabrication processes. 
         [0009]    The technical solutions of the present invention are as follows: 
         [0010]    A thin-film thermo-electric generator comprises a substrate, a P-type thermo-electric thin-film layer, an insulating thin-film layer and a N-type thermo-electric thin-film layer is repeatedly deposited in turns on one side of said substrate, a group of said P-type thermo-electric thin-film layer, said insulating thin-film layer and said N-type thermo-electric thin-film layer forms a three-layer structure, said P-type thermo-electric thin-film layer and said N-type thermo-electric thin-film layer of said three-layer structure is connected in one end of said insulating thin-film layer to form a PN junction, an insulating layer is provided between two said adjacent PN junctions, and said two adjacent PN junctions is connected in one end of said insulating layer, in order to form a serial PN junction, an electrode is extracted from the outermost thin-film layer on one side of said substrate and another electrode is extracted from one side of the substrate deposited by thermo-electric thin-film layer. 
         [0011]    A thin-film thermo-electric generator, wherein the thickness range of said substrate is 0.1 mm-100 mm, the thickness range of said P-type thermo-electric thin-film layer is 1 nm-10 μm, the thickness range of said N-type thermo-electric thin-film layer is 1 nm-10 μm. 
         [0012]    A thin-film thermo-electric generator, wherein the shape of said substrate is regular rectangle. 
         [0013]    A thin-film thermo-electric generator comprises a substrate, a P-type thermo-electric thin-film layer, an insulating thin-film layer and a N-type thermo-electric layer is repeatedly deposited in turns on one side of said substrate, a group of said P-type thermo-electric thin-film layer, said insulating thin-film layer and said N-type thermo-electric thin-film layer forms a three-layer structure, said P-type thermo-electric thin-film layer and said N-type thermo-electric thin-film layer of said three-layer structure is connected in one end of said insulating thin-film layer to form a PN junction, an insulating layer is provided between two said adjacent PN junctions, and said two adjacent PN junctions is connected in one end of the insulating layer, in order to form a serial PN junction, two electrodes is respectively extracted from the outermost thin-film layer on two sides of said substrate. 
         [0014]    A method for fabrication a thin-film thermo-electric generator comprises steps as follows: 
         [0015]    selecting a substrate and sheltering one side of said substrate; 
         [0016]    presetting an electrode on a surface of said substrate; 
         [0017]    depositing a P-type thermo-electric thin-film layer on the side of the substrate on which the electrode is preset; 
         [0018]    sheltering said substrate, one end and all sides of deposited thin-film layer, depositing an insulating thin-film layer on said P-type thermo-electric thin-film layer; 
         [0019]    sheltering said substrate and all sides of deposited thin-film layer, depositing a N-type thermo-electric thin-film layer on said insulating thin-film layer to form a three-layer structure, the P-type thermo-electric thin-film layer and N-type thermo-electric thin-film layer of said three-layer structure is connected in said sheltered end of the substrate to form a PN junction; 
         [0020]    repeating above-said steps to form multiple PN junctions; 
         [0021]    sheltering said substrate, the other end and all sides of the deposited thin-film layers, depositing an insulating thin-film layer between every two adjacent PN junctions, said two adjacent three-layer PN junctions are connected in the other end of said deposited thin-film layers to form a PN junction in series: 
         [0022]    extracting another electrode from the outermost thin-film layer of the last three-layer PN junction, to form the main structure of a thin-film thermo-electric generator. 
         [0023]    A method for fabrication a thin-film thermo-electric generator, depositing multilayer on the two sides of the substrate, and further comprises steps as follows: 
         [0024]    selecting a substrate and sheltering one side of said substrate; 
         [0025]    depositing a P-type thermo-electric thin-film layer on the side of the substrate; 
         [0026]    sheltering said substrate, one end and all sides of deposited thin-film layer, depositing an insulating thin-film layer on said P-type thermo-electric thin-film layer; 
         [0027]    sheltering said substrate and all sides of deposited thin-film layer, depositing a N-type thermo-electric thin-film layer on said insulating thin-film layer to form a three-layer structure, the P-type thermo-electric thin-film layer and N-type thermo-electric thin-film layer of said three-layer structure is connected in said sheltered end of the substrate to form a PN junction; 
         [0028]    repeating above-said steps to form multiple PN junctions; 
         [0029]    sheltering said substrate, the other end and all sides of the deposited thin-film layers, depositing an insulating thin-film layer between every two adjacent PN junctions, said two adjacent three-layer PN junctions are connected in the other end of said deposited thin-film layers to form a PN junction in series; 
         [0030]    extracting another electrode from the outermost thin-film layer of the last three-layer PN junction; 
         [0031]    repeating above-said steps to form multiple serial three-layer PN junctions on the other side of said substrate, extracting another electrode from the outermost thin-film layer of the last three-layer PN junction on the other side of said substrate, to form the main structure of a thin-film thermo-electric generator. 
         [0032]    For the thin-film thermo-electric generator and fabrication method of this invention, a P-type thermo-electric thin-film layer, an insulating thin-film layer and a N-type thermo-electric thin-film layer is deposited on a substrate to form a three-layer PN (Positive-Negative) junction, multiple three-layer PN junctions in series are available, an insulating thin-film layer is provided between every to serial three-layer PN junctions, and electrodes are extracted from the substrate and the outermost thin-film layer of the last three-layer thin-film PN junctions. The present invention applies the deposition of P-type thermo-electric thin-film layer, an insulating thin-film layer and a N-type thermo-electric thin-film layer to form a three-layer PN junction, thus thermo-electric generator is formed, during the deposition of the insulating thin-film layer, intentionally sheltering the substrate and one end of the deposited thin-film layer and depositing the P-type or N-type materials on the substrate and one end of the deposited thin-film layer directly, to form a connection of PN junction or a serial connection between two PN junction, the separate connection of the P-type or N-type materials is not required, simplifying the fabrication processes of the thin-film thermo-electric generator, owning to the characteristics of the thin-film thermo-electric materials and serial connection structure of multiple three-layer PN junctions, the performance of the thin-film thermo-electric generator is greatly improved. 
         [0033]    Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings. 
         [0034]    These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0035]      FIG. 1 a   - FIG. 1 i    are the schematic diagrams of the fabrication process of the first embodiment of the invention. 
           [0036]      FIG. 2 a   - FIG. 2 h    are the schematic diagrams of the fabrication process of the second embodiment of the invention. 
           [0037]      FIG. 3 a   - FIG. 3 g    are the schematic diagrams of the fabrication process of the third embodiment of the invention. 
           [0038]      FIG. 4 a   - FIG. 4 h    are the schematic diagrams of the fabrication process of the forth embodiment of the invention. 
           [0039]      FIG. 5 a   - FIG. 5 g    are the schematic diagrams of the fabrication process of the fifth embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0040]    The following description is disclosed to enable any person skilled in the art to make and use the present invention. Preferred embodiments are provided in the following description only as examples and modifications will be apparent to those skilled in the art. The general principles defined in the following description would be applied to other embodiments, alternatives, modifications, equivalents, and applications without departing from the spirit and scope of the present invention. 
         [0041]    The present invention provides a thin-film thermo-electric generator and fabrication method thereof. To make the technical solutions of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and embodiments as follows. 
       The First Embodiment 
       [0042]      FIG. 1 a   - FIG. 1 i    are the schematic diagrams of the fabrication process of the first embodiment of the invention.  FIG. 1 i    is the schematic diagrams of the end of the thin-film thermo-electric generator. In the first embodiment, the thin-film thermo-electric generator comprises an insulating substrate  101 , an extractive electrode  102 , a P-type thermo-electric thin-film layer  103 , an insulating thin-film layer  104 , a N-type thermo-electric thin-film layer  105 , an insulating thin-film layer  106 , a P-type thermo-electric thin-film layer  107 , an insulating thin-film layer  108 , a N-type thermo-electric thin-film layer  109 , and an extractive electrode  110 . 
         [0043]      FIG. 1 a    shows a preset electrode  102  on a surface of the insulating substrate  101 . 
         [0044]      FIG. 1 b    shows a P-type thermo-electric thin-film layer  103  deposited on the side of the substrate on which the electrode is preset. 
         [0045]      FIG. 1 c    shows an insulating thin-film layer  104  deposited on the P-type thermo-electric thin-film layer  103 . 
         [0046]      FIG. 1 d    shows a N-type thermo-electric thin-film layer  105  deposited on the insulating thin-film layer  104 . 
         [0047]      FIG. 1 e    shows an insulating thin-film layer  106  deposited on the N-type thermo-electric thin-film layer  105 . 
         [0048]      FIG. 1 f    shows a P-type thermo-electric thin-film layer  107  deposited on the insulating thin-film layer  106 . 
         [0049]      FIG. 1 g    shows an insulating thin-film layer  108  deposited on the P-type thermo-electric thin-film layer  107 . 
         [0050]      FIG. 1 h    shows a N-type thermo-electric thin-film layer  109  deposited on the insulating thin-film layer  108 . 
         [0051]      FIG. 1 i    shows the formation of an insulating thin-film layer  116 , a P-type thermo-electric thin-film layer  117 , an insulating thin-film layer  118  and a N-type thermo-electric thin-film layer  119 . 
         [0052]    The P-type thermo-electric thin-film layer and the N-type thermo-electric thin-film layer is connected in one end of the insulating thin-film layer to form a three-layer PN junction. An insulating layer is provided between two adjacent PN junctions, and the two adjacent PN junctions is connected in one end of the insulating layer, in order to form a serial PN junction. Another electrode  110  is provided in the N-type thermo-electric thin-film layer  119  of the last three-layer PN junction. Thus, the main structure of thin-film thermo-electric generator as shown in  FIG. 1 i    is formed. Then the thin-film thermo-electric generator is made by scribing, racking, packaging and related subsequent procedures. 
         [0053]    The general materials of the thin-film thermo-electric generator are metal and semiconductor. The P-type and N-type thermo-electric materials in the embodiment of this invention may be two different metals or semiconductors made by depositing two different metal layers or semiconductors to form a thermo-electric generator. During the fabrication process, the depositing of N-type thermo-electric layer can be carried before or after the depositing of P-type thermo-electric thin-film layer. 
         [0054]    Several methods can be applied to make the P-type and N-type thermo-electric thin-film layers, such as vacuum evaporation, Molecule Beam Epitaxy (MBE), magnetron sputtering, ion beam sputtering deposition, Laser Deposition, electrochemical atomic layer epitaxy (ECALE), metal-organic chemical vapor deposition (MOCVD), and successive ionic layer adsorption and reaction (SILAR). The first embodiment of the invention provides a fabrication process of the thin-film thermo-electric generator with the ion beam sputtering deposition: 
         [0055]    The device is an ultrahigh vacuum ion beam sputtering deposition system. Selecting targets of P-type and N-type metals S.sub.b, B.sub.i and insulating material Al 2 O 3 , the purity of the target is 99.99%, and setting these targets in the target position respectively. Conducting ultrasonic washing on the substrate of common soda-lime glass, and put it in clamping fixture in the deposition room. The fixture may further have apparatuses for intentional sheltering in the two ends and the sides. In the room temperature, the deposition is carried by adjusting the targets and ion beam sputtering deposition, the procedures is as below: 
         [0056]    Step 1: as shown in  FIG. 1   a,  sheltering all sides of the glass substrate  101  other than in the area of the preset electrode  102 . 
         [0057]    Step 2: as shown in  FIG. 1   b,  depositing a 300 nm thick S b  thin-film layer  103  on the side of the substrate  101  on which the electrode is preset. 
         [0058]    Step 3: as shown in  FIG. 1   c,  sheltering the substrate  101 , one end and all sides of the S b  thin-film layer  103 , and depositing a 500 nm thick Al 2 O 3  thin-film layer  104  on the S b  thin-film layer  103 . 
         [0059]    Step 4: as shown in  FIG. 1   d,  sheltering the substrate  101  and all sides of the deposited thin-film layers, and depositing a 300 nm thick B i  thin-film layer  105  on the deposited Al 2 O 3  thin-film layer  104 , the S b  thin-film layer  103  and the Bi thin-film layer  105  is connected in one end of the Al 2 O 3  thin-film layer  104  to form the first PN junction. 
         [0060]    Step 5: as shown in  FIG. 1   e,  sheltering the substrate  101  and all sides of the deposited thin-film layers, and depositing a 500 nm thick Al 2 O 3  thin-film layer  106  on the Bi thin-film layer  105 . 
         [0061]    Step 6: as shown in  FIG. 1   f,  sheltering the substrate  101  and all sides of the deposited thin-film layers, and depositing a 300 nm thick S b  thin-film layer  107  on the Al 2 O 3  thin-film layer  106 , the S b  thin-film layer  107  and the B i  thin-film layer  105  is connected in one end of the Al 2 O 3  thin-film layer  106  to form a connecting port between the first and the second PN junction. 
         [0062]    Step 7 as shown in  FIG. 1   g,  sheltering the substrate  101 , one end and all sides of the deposited thin-film layers, and depositing a 500 nm thick Al 2 O 3  thin-film layer  108  on the S b  thin-film layer  107 . 
         [0063]    Step 8: as shown in  FIG. 1   h,  sheltering the substrate  101  and all sides of the deposited thin-film layers, and depositing a 300 nm thick B i  thin-film layer  109  on the Al 2 O 3  thin-film layer  108 , the S b  thin-film layer  107  and the B i  thin-film layer  109  is connected in one end of the Al 2 O 3  thin-film layer  108  to form a second PN junction. The first and the second PN junction is connected in series through the Al 2 O 3  thin-film layer  106 . 
         [0064]    Step 9: as shown in  FIG. 1   i,  repeating the steps from Step 5 to Step 8 to form a Al 2 O 3  thin-film layer  116 , a S b  thin-film layer  117 , a Al 2 O 3  thin-film layer  118 , and a B i  thin-film layer  119  respectively, accordingly a connection in series between a PN junction and a deposited PN junction is made, the connection of multiple three-layer PN junctions in series is available, an insulating layer is set among every three-layer PN junctions. During the deposition, the background vacuum degree is 4.5×10 −4  Pa, the working vacuum degree is 4.1×10 −2  Pa, and the working gas is 99.99% pure Ar with a rate of flow of 4 sccm. The technical parameters of the ion beam sputtering deposition are as below: plate voltage 1 KV, anode voltage 75V, acceleration voltage 220V, cathode voltage 7V, cathode current 11 A, and beam 14 mA. After obtaining one or multiple three-layer PN junctions in series by depositing on the substrate  101 , another electrode  110  is extracted from the B.sub.i thin-film layer  119  in the last PN junction, thus the main structure of the thin-film thermo-electric generator as shown in  FIG. 1 i    is formed. 
         [0065]    During the above-said fabrication process, the depositing of N-type thermo-electric thin-film layer can be carried before or after the depositing of P-type thermo-electric thin-film layer. 
         [0066]    In the first embodiment of this invention, the fabrication processes of thin-film thermo-electric generator with the magnetron sputtering are as below: 
         [0067]    The device is a three-target magnetron sputtering system. Selecting targets of metals S b , B i  and Al, the purity of the target is 99.99%, and setting these targets in the target position respectively. Conducting ultrasonic washing on the substrate of common soda-lime glass, and put it in fixture in the deposition room. The fixture may further have apparatuses for intentional sheltering in the two ends and the sides. In the room temperature, during the deposition, the background vacuum is 4.5×10 −3  Pa, the working vacuum is 4.1×10 −2  Pa. During the deposition of S b  and B i  thin-film layer with DC magnetron sputtering, the working gas is 99.99% pure Ar with a rate of flow of 50 sccm. During the deposition of the Al 2 O 3  thin-film layer with direct current magnetron reactive sputtering, the working gas is 99.99% pure Ar with a rate of flow of 50 sccm and the reactive gas 99.99% pure O2 with a rate of flow of 50 sccm. The processes of deposition are described as follows: 
         [0068]    Step 1: as shown in  FIG. 1   a,  sheltering all sides of the glass substrate  101  other than in the area of the preset electrode  102 . 
         [0069]    Step 2: as shown in  FIG. 1   b,  depositing a 300 nm thick S b  thin-film layer  103  n the side of the substrate  101  on which the electrode is preset. 
         [0070]    Step 3: as shown in  FIG. 1   c,  sheltering the substrate  101 , one end and all sides of the S b  thin-film layer  103 , and depositing a 500 nm thick Al 2 O 3  thin-film layer  104  on the S b  thin-film layer  103 . 
         [0071]    Step 4: as shown in  FIG. 1   d,  sheltering the substrate  101  and all sides of the deposited thin-film layers, and depositing a 300 nm thick B i  thin-film layer  105  on the deposited Al 2 O 3  thin-film layer  104 , the S b  thin-film layer  103  and the B i  thin-film layer  105  is connected in one end of the Al 2 O 3  thin-film layer  104  to form the first PN junction. 
         [0072]    Step 5: as shown in  FIG. 1   e,  sheltering the substrate  101  and all sides of the deposited thin-film layers. and depositing a 500 nm thick Al 2 O 3  thin-film layer  106  on the B i  thin-film layer  105 . 
         [0073]    Step 6: as shown in  FIG. 1   f,  sheltering the substrate  101  and all sides of the deposited thin-film layers, and depositing a 300 nm thick S b  thin-film layer  107  on the Al 2 O 3  thin-film layer  106 , the S b  thin-film layer  107  and the B i  thin-film layer  105  is connected in one end of the Al 2 O 3  thin-film layer  106  to form a connecting port between the first and the second PN junction. 
         [0074]    Step 7 as shown in  FIG. 1   g,  sheltering the substrate  101 , one end and all sides of the deposited thin-film layers, and depositing a 500 nm thick Al 2 O 3  thin-film layer  108  on the S b  thin-film layer  107 . 
         [0075]    Step 8: as shown in  FIG. 1   h,  sheltering the substrate  101  and all sides of the deposited thin-film layers, and depositing a 300 nm thick B i  thin-film layer  109  on the Al 2 O 3  thin-film layer  108 , the S.sub.b thin-film layer  107  and the B i  thin-film layer  109  is connected in one end of the Al 2 O 3  thin-film layer  108  to form a second PN junction. The first and the second PN junction is connected in series through the Al 2 O 3  thin-film layer  106 . 
         [0076]    Step 9: as shown in  FIG. 1   i,  repeating the steps from Step 5 to Step 8 to form a Al.sub.2O.sub.3 thin-film layer  116 , a S b  thin-film layer  117 , a Al 2 O 3  thin-film layer  118 , and a B i  thin-film layer  119  respectively, accordingly a connection in series between a PN junction and a deposited PN junction is made, the connection of multiple three-layer PN junctions in series is available, an insulating layer is set among every three-layer PN junctions. During the deposition, the background vacuum is 4.5×10 −4  Pa, the working vacuum is 4.1×10 −3  Pa, and the working gas is 99.99% pure Ar with a rate of flow of 4 sccm. The technical parameters of the ion beam sputtering deposition are as below: plate electrode voltage 1 KV, anode voltage 75V, acceleration voltage 220V, cathode voltage 7V, cathode current 11 A, and beam 14 mA. After obtaining one or multiple three-layer PN junctions in series by depositing on the substrate  101 , another electrode  110  is extracted from the B i  thin-film layer  119  in the last PN junction, thus the main structure of the thin-film thermo-electric generator as shown in  FIG. 1 i    is formed. 
         [0077]    During the above-said fabrication process, the depositing of N-type thermo-electric thin-film layer can be carried before or after the depositing of P-type thermo-electric thin-film layer. 
       Second Embodiment 
       [0078]    The thin-film thermo-electric generator can be made by using the insulating substrate as well as the substrate of P-type thermo-electric material (or metal) or N-type thermo-electric material (or metal). If the substrate of P-type thermo-electric material is applied, the cross-section diagram of the thin-film thermo-electric generator is shown in  FIG. 2   h.  In this embodiment, the thin-film thermo-electric generator comprises a P-type thermo-electric material substrate  201 , an insulating thin-film layer  202 , a N-type thermo-electric thin-film layer  203 , an insulating thin-film layer  204 , a P-type thermo-electric thin-film layer  205 , an insulating thin-film layer  206 , a N-type thermo-electric thin-film layer  207 , an extractive electrode  208  and an extractive electrode  209 . 
         [0079]      FIG. 2 a    shows the insulating thin-film layer  202  deposited on the P-type thermo-electric material substrate  201 . 
         [0080]      FIG. 2 b    shows the N-type thermo-electric thin-film layer  203  deposited on the insulating thin-film layer  202 . 
         [0081]      FIG. 2 c    shows the insulating thin-film layer  204  deposited on the N-type thermo-electric thin-film layer  203 . 
         [0082]      FIG. 2 d    shows the P-type thermo-electric thin-film layer  205  deposited on the insulating thin-film layer  204 . 
         [0083]      FIG. 2 e    shows the insulating thin-film layer  206  deposited on the P-type thermo-electric thin-film layer  205 . 
         [0084]      FIG. 2 f    shows the N-type thermo-electric thin-film layer  207  deposited on the insulating thin-film layer  206 . 
         [0085]      FIG. 2 g    shows the formation of an insulating thin-film layer  214 , a P-type thermo-electric thin-film layer  215 , an insulating thin-film layer  216  and a N-type thermo-electric thin-film layer  217 . 
         [0086]    In order to form a connection of a PN junction and a deposited PN junction in series, multiple connections of three-layer PN junctions in series may be applied, and an insulating thin-film layer is applied among the PN junctions. The three-layer P-type thermo-electric thin-film layer and the N-type thermo-electric thin-film layer is connected in one end of the insulating thin-film layer to form a PN junction. An insulating layer is provided between two adjacent PN junctions, and the two adjacent three-layer PN junctions is connected in one end of the insulating layer, in order to form a serial PN junction. An electrode  208  is provided in the N-type thermo-electric thin-film layer  217  of the last three-layer PN junction, an electrode  209  is provided in the side which is not deposited in the P-type thermo-electric material substrate  201 . Thus, the main structure of the thin-film thermo-electric generator based on the P-type thermo-electric material substrate as shown in  FIG. 2 h    is formed. 
         [0087]    For the improvement of second embodiment, if the N-type thermo-electric material is applied as the substrate, the fabrication process of the N-type thermo-electric thin-film layer and the P-type thermo-electric thin-film layer shall be exchanged. 
       The Third Embodiment 
       [0088]    The embodiment of the present invention has some other variations. For example, based on the structure of thin-film thermo-electric generator applying P-type thermo-electric material as the substrate as shown in  FIG. 2   g,  depositing multiple connections in series of three-layer PN junctions on the other side of the P-type thermo-electric substrate  201 , an insulating thin-film layer is provided between every three-layer PN junction, to form a thin-film thermo-electric generator provided in the third embodiment. As shown in  FIG. 3   g,  the thin-film thermo-electric generator in this embodiment comprises a substrate  301  of P-type thermo-electric material as the base of thin-film thermo-electric generator structure, an insulating thin-film layer  302 , a N-type thermo-electric thin-film layer  303 , an insulating thin-film layer  304 , a P-type thermo-electric thin-film layer  305 , an extractive electrode  208  and an extractive electrode  209 . 
         [0089]      FIG. 3 a    shows a substrate  301  of P-type thermo-electric material as the base of thin-film thermo-electric generator structure in the  FIG. 2   g.    
         [0090]      FIG. 3 b    shows an insulating thin-film layer  302  deposited on the other side of the substrate  301  of P-type thermo-electric material as the base of thin-film thermo-electric generator structure in the second embodiment of this invention. 
         [0091]      FIG. 3 c    shows a N-type thermo-electric thin-film layer  303  deposited on the insulating thin-film layer  302 . 
         [0092]      FIG. 3 d    shows the insulating thin-film layer  304  deposited on the N-type thermo-electric thin-film layer  303 . 
         [0093]      FIG. 3 e    shows the P-type thermo-electric thin-film layer  305  deposited on the insulating thin-film layer  304 . 
         [0094]      FIG. 3 f    shows the formation of an insulating thin-film layer  312 , a P-type thermo-electric thin-film layer  313 , an insulating thin-film layer  314  and a N-type thermo-electric thin-film layer  315 . Multiple connections of three-layer PN junctions in series are available, an insulating thin-film is applied between every PN junctions. The three-layer P-type thermo-electric thin-film layer and N-type thermo-electric thin-film layer is connected in one end of the insulating thin-film layer, to form a PN junction. An insulating thin-film layer is applied between every PN junction, and the PN junctions are connected in one end of the insulating thin-film layer, to form connections of PN junctions in series. 
         [0095]    An electrode  306  and an electrode  307  is extracted from the N-type thermo-electric thin-film layer of the last three-layer PN junction in the two sides of the P-type thermo-electric thin-film substrate to form the main structure of the thin-film thermo-electric generator deposited on the two-side P-type thermo-electric thin-film substrate. 
         [0096]    For the improvement of the third embodiment, if the N-type thermo-electric material is applied as the substrate, the fabrication process of the N-type thermo-electric thin-film layer and the P-type thermo-electric thin-film layer shall be exchanged. 
       The Fourth Embodiment 
       [0097]    The thin-film thermo-electric generator based on insulating substrate in the first embodiment may have the structure as follows: 
         [0098]      FIG. 4 h    is the cross-section view of the thin-film thermo-electric generator of this invention, which comprises an insulating substrate  401 , a P-type thermo-electric thin-film layer  402 , a N-type thermo-electric thin-film layer  403 , an insulating thin-film layer  404 , a P-type thermo-electric thin-film layer  405 , an insulating thin-film layer  406 , a N-type thermo-electric thin-film layer  407 , an extractive electrode  408  and an extractive electrode  409 . 
         [0099]      FIG. 4 a    shows the P-type thermo-electric thin-film layer  402  deposited on one side of the insulating substrate  401 ; 
         [0100]      FIG. 4 b    shows the N-type thermo-electric thin-film layer  403  deposited on the other side of the insulating substrate  401 ; 
         [0101]      FIG. 4 c    shows the insulating thin-film layer  404  deposited on the N-type thermo-electric thin-film layer  403 ; 
         [0102]      FIG. 4 d    shows the P-type thermo-electric thin-film layer  405  deposited on the insulating thin-film layer  404 ; 
         [0103]      FIG. 4 e    shows the insulating thin-film layer  406  deposited on the P-type thermo-electric thin-film layer  405 ; 
         [0104]      FIG. 4 f    shows N-type thermo-electric thin-film layer  407  deposited on the insulating thin-film layer  406 ; 
         [0105]      FIG. 4 g    shows the formation of an insulating thin-film layer  414 , a P-type thermo-electric thin-film layer  415 , an insulating thin-film layer  416  and a N-type thermo-electric thin-film layer  417 . Multiple connections of three-layer PN junctions in series are available, an insulating thin-film is applied between every PN junctions. The three-layer P-type thermo-electric thin-film layer and N-type thermo-electric thin-film layer is connected in one end of the insulating thin-film layer, to form a PN junction. An insulating thin-film layer is applied between every PN junction, and the PN junctions are connected in one end of the insulating thin-film layer, to form connections of PN junctions in series. An electrode  408  and an electrode  409  is extracted from the N-type thermo-electric thin-film layer of last three-layer PN junction on the two sides of the insulating substrate. 
       The Fifth Embodiment 
       [0106]    Based on the structure of thin-film thermo-electric generator applying P-type thermo-electric material as the substrate as shown in  FIG. 4   g,  depositing multiple connections in series of three-layer PN junctions on the other side of the P-type thermo-electric substrate, an insulating thin-film layer is provided between every three-layer PN junctions, to form a thin-film thermo-electric generator provided in the third embodiment. As shown in  FIG. 5   g,  the thin-film thermo-electric generator in this embodiment comprises a base  501  of the thin-film thermo-electric generator structure shown in  FIG. 4   g,  an insulating thin-film layer  502 , a N-type thermo-electric thin-film layer  503 , an insulating thin-film layer  504 , a P-type thermo-electric thin-film layer  505 , an extractive electrode  506  and an extractive electrode  507 . 
         [0107]      FIG. 5 a    shows the base  501  of the thin-film thermo-electric generator; 
         [0108]      FIG. 5 b    shows an insulating thin-film layer  502  deposited on the base  501  of the P-type thermo-electric thin-film layer in the other side of the substrate of the thin-film thermo-electric generator as shown in  FIG. 4   g;    
         [0109]      FIG. 5 c    shows the N-type thermo-electric thin-film layer  503  deposited on the insulating thin-film layer  502 ; 
         [0110]      FIG. 5 d    shows the insulating thin-film layer  504  deposited on the N-type thermo-electric thin-film layer  503 ; 
         [0111]      FIG. 5 e    shows the P-type thermo-electric thin-film layer  505  deposited on the insulating thin-film layer  504 ; 
         [0112]      FIG. 5 f    shows the formation of an insulating thin-film layer  512 , a P-type thermo-electric thin-film layer  513 , an insulating thin-film layer  514  and a N-type thermo-electric thin-film layer  515 . Multiple connections of three-layer PN junctions in series are available, an insulating thin-film is applied between every PN junctions. The three-layer P-type thermo-electric thin-film layer and N-type thermo-electric thin-film layer is connected in one end of the insulating thin-film layer, to form a PN junction. An insulating thin-film layer is applied between every PN junction, and the PN junctions are connected in one end of the insulating thin-film layer, to form connections of PN junctions in series. 
         [0113]    An electrode  506  and an electrode  507  is extracted from the N-type thermo-electric thin-film layer of last three-layer PN junction on the two sides of the insulating substrate. Thus, the main structure of the thin-film thermo-electric generator two-sides deposited on the P-type thermo-electric material substrate as shown in  FIG. 5 g    is formed. 
         [0114]    During the above-said fabrication process in the fifth embodiment, the depositing of N-type thermo-electric thin-film layer can be carried before or after the depositing of P-type thermo-electric thin-film layer. 
         [0115]    In all the above-said embodiments, the substrate can be regular a rectangle or a square or in any irregular shapes. The common thickness range of the substrate is from 0.1 mm to 100 mm. The substrate can be an insulating substrate, a P-type thermo-electric thin-film or a N-type thermo-electric thin-film substrate, or any other material substrate. The P-type and N-type thermo-electric thin-film materials in the thin-film thermo-electric generator can be the same or different, this is, in the whole thin-film thermo-electric generator, the PN junction can be made by two different metal thin-film layer and insulating layer, and can also be made by a pair of P-type and N-type thermo-electric thin-film layers and insulating layer. During the deposition of insulating layers, one end of them is deliberately sheltered. Wherein, the ion beam sputtering deposition and magnetron sputtering in the first embodiment can also be applied in the second, third, fourth and fifth embodiment, and some other methods such as vacuum evaporation, Molecule Beam Epitaxy (MBE), Laser Deposition, electrochemical atomic layer epitaxy (ECALE), metal-organic chemical vapor deposition (MOCVD), and successive ionic layer adsorption and reaction (SILAR) can be applied. Then the thin-film thermo-electric generator is made by scribing, racking, packaging and related subsequent procedures. 
         [0116]    Thermo-electric phenomenon is reversible, and the semiconductor thermo-electric generation and refrigeration can be reversible. For a single PN junction, if the temperature difference is used for electricity generation, then the electricity can be used for refrigeration in the other end. Thus, the main thin-film thermo-electric generator structure can be the main structure of the thin-film thermo-electric cooler. The invention may be embodied in other specific form without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. 
         [0117]    One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting. 
         [0118]    It will thus be seen that the objects of the present invention have been fully and effectively accomplished. The embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.