Method of fabricating integrated thin film solar cells

• US 5,956,572 A
• Filed: 08/25/1997
• Issued: 09/21/1999
• Est. Priority Date: 08/26/1996
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Umemoto, Akimasa, Kidoguchi, Susumu
• Primary Examiner(s): Dutton, Brian
• Application Number:
  US08/917,105
• Time in Patent Office: 757 Days
• Field of Search: 257/53, 136/258, 136/244, 438/96, 438/940, 438/98
• US Class Current: 438/96
• CPC Class Codes: B23K 2103/172 wherein at least one of the layers is non-metallic
• CPC Class Codes: B23K 26/364 for making a groove or trench, e.g. for scribing a break initiation groove
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: H01L 31/03921 including only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/046 PV modules composed of a plurality of thin film solar cells deposited on the same substrate
• CPC Class Codes: H01L 31/0463 characterised by special patterning methods to connect the PV cells in a module, e.g. laser cutting of the conductive or active layers
• CPC Class Codes: H01L 31/056 the light-reflecting means being of the back surface reflector [BSR] type
• CPC Class Codes: H01L 31/1884 Manufacture of transparent electrodes, e.g. TCO, ITO
• CPC Class Codes: H01L 31/202 including only elements of Group IV of the Periodic Table
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10S 438/94 Laser ablative material removal

Abstract

A method is provided for fabricating solar cells. A transparent conductive film is formed on a transparent substrate having an insulative surface and the transparent conductive film is segmented by a first scribing step to form transparent conductive film electrodes. An amorphous semiconductor layer is formed on the resulting substrate having the transparent conductive film electrodes. The amorphous semiconductor layer is segmented by a second scribing step to form amorphous semiconductor photoelectric conversion layers. A rear electrode layer is formed on the resulting substrate having the amorphous semiconductor photoelectric conversion layers and this rear electrode layer is segmented by a third scribing step to form rear electrodes. The third scribing step includes forming a resist film on the rear electrode layer, forming trenches in the resist film by laser scribing and etching off portions of the rear electrode layer with an etchant by using the resulting resist film as a mask.

Claims

1. A method of fabricating integrated thin film solar cells, comprising:

a step for forming a transparent conductive film on a transparent substrate having an insulative surface;

a first scribing step for segmenting the transparent conductive film to form transparent conductive film electrodes;

a step for forming an amorphous semiconductor layer on the resulting substrate having the transparent conductive film electrodes;

a second scribing step for segmenting the amorphous semiconductor layer to form amorphous semiconductor photoelectric conversion layers;

a step for forming a rear electrode layer on the resulting substrate having the amorphous semiconductor photoelectric conversion layers; and

a third scribing step for segmenting the rear electrode layer to form rear electrodes;

wherein the third scribing step includes forming a resist film on the rear electrode layer, forming trenches in the resist film by laser scribing, and etching off portions of the rear electrode layer with an etchant by using the resulting resist film as a mask.

2. A method of claim 1, wherein the transparent substrate is subjected to a texturing treatment before the formation of the transparent conductive film.

3. A method of claim 1, wherein the rear electrode layer comprises a transparent conductive film and a metal reflection film.

4. A method of claim 3,

wherein the metal reflection film is formed of silver;

the resist film is formed on the metal reflection film; and

then the trenches are formed in the resist film by irradiation with a laser beam having a wavelength of 0.45 μ

m or greater.

5. A method of claim 3,

wherein the metal reflection film is formed of aluminum;

the resist film is formed on the metal reflection film; and

then the trenches are formed in the resist film by irradiation with a laser beam having a wavelength of 0.10 μ

m or greater.

6. A method of claim 1, wherein the formation of the resist film is achieved by a screen printing, spray coating or spin coating method.

7. A method of fabricating solar cells, comprising:

successively forming transparent first electrodes, solar cells and second electrodes on the surface of a transparent substrate,

wherein said second electrodes are formed by forming a second electrode layer over said solar cells, forming a resist over said second electrode layer, forming trenches in said resist by laser scribing, and etching off portions of said second electrode layer with an etchant using the laser-scribed resist film as a mask.

8. A method of claim 7, wherein said transparent first electrodes are formed by forming a transparent conductive film on the surface of said transparent substrate;

and irradiating the transparent conductive film with a laser beam to segment said transparent conductive film.

9. A method of claim 8, wherein said transparent conductive film is formed of one material selected from the group consisting of indium tin oxide, zinc oxide, and tin oxide.

10. A method of claim 7, wherein said solar cells are formed by forming an amorphous semiconductor layer on said transparent first electrodes;

and irradiating the amorphous semiconductor layer with a laser beam to segment said amorphous semiconductor layer.

11. A method of claim 10, wherein said amorphous semiconductor layer comprises a p-layer, an i-layer and an n-layer.

12. A method of claim 11, wherein each of said p-layer, said i-layer and said n-layer is amorphous.

13. A method of claim 11, wherein said p-layer is amorphous and said i-layer and said n-layer are crystalline.

14. A method of claim 7, wherein said second electrode layer comprises a transparent conductive film and a reflection film.

15. A method of claim 14, wherein said transparent conductive film is formed of one material selected from the group consisting of indium tin oxide, zinc oxide, and tin oxide.

16. A method according to claim 14, wherein said reflection film is formed of one material selected from the group consisting of silver and aluminum.

17. A method according to claim 7, wherein the surface of said transparent substrate is textured prior to forming said transparent conductive electrodes.