Protection layer for fabricating a solar cell

Abstract

A method for fabricating a solar cell is described. The method includes first providing, in a process chamber, a substrate having a light-receiving surface. An anti-reflective coating (ARC) layer is then formed, in the process chamber, above the light-receiving surface of the substrate. Finally, without removing the substrate from the process chamber, a protection layer is formed above the ARC layer.

1 . A method for fabricating a solar cell, comprising:
 providing, in a process chamber, a substrate having a light-receiving surface;   forming, in the process chamber, an anti-reflective coating (ARC) layer above the light-receiving surface of the substrate; and   depositing, in the process chamber, an etchant-resistive protection layer above the ARC layer.   
   
   
       2 . The method of  claim 1 , wherein the etchant-resistive protection layer comprises amorphous carbon. 
   
   
       3 . The method of  claim 2 , wherein the etchant-resistive protection layer is deposited by vapor deposition using a gas selected from the group consisting of methane (CH 4 ), ethane (C 2 H 6 ), propane (C 3 H 8 ), ethylene (C 2 H 4 ), propylene (C 3 H 6 ), and liquid toluene (C 7 H 8 ) transported by a carrier gas selected from the group consisting of argon (Ar), nitrogen (N 2 ), helium (He) and hydrogen (H 2 ). 
   
   
       4 . The method of  claim 1 , wherein the etchant-resistive protection layer comprises amorphous silicon. 
   
   
       5 . The method of  claim 4 , wherein the etchant-resistive protection layer is deposited by vapor deposition using silane (SiH 4 ) gas. 
   
   
       6 . The method of  claim 1 , wherein the etchant-resistive protection layer is deposited to a thickness approximately in the range of 1-30 nanometers. 
   
   
       7 . The method of  claim 1 , wherein both the ARC layer and the etchant-resistive protection layer are formed by a technique selected from the group consisting of chemical vapor deposition, plasma-enhanced chemical vapor deposition, atmospheric-pressure chemical vapor deposition and physical vapor deposition. 
   
   
       8 . The method of  claim 1 , wherein the etchant-resistive protection layer is resistant to a buffered oxide etch (BOE). 
   
   
       9 . A method for fabricating a solar cell, comprising:
 providing a substrate having a light-receiving surface and a second surface with a plurality of active regions;   forming, in a process chamber, an anti-reflective coating (ARC) layer above the light-receiving surface of the substrate; and   depositing, in the process chamber, an etchant-resistive protection layer above the ARC layer;   forming, using a buffered oxide etch (BOE), a plurality of contact openings to the plurality of active regions at the second surface of the substrate, wherein the etchant-resistive protection layer protects the ARC layer during the forming of the plurality of contact openings; and   forming a plurality of contacts in the plurality of contact openings.   
   
   
       10 . The method of  claim 9 , wherein the etchant-resistive protection layer comprises amorphous carbon. 
   
   
       11 . The method of  claim 10 , wherein the etchant-resistive protection layer is deposited by vapor deposition using a gas selected from the group consisting of methane (CH 4 ), ethane (C 2 H 6 ), propane (C 3 H 8 ), ethylene (C 2 H 4 ), propylene (C 3 H 6 ), and liquid toluene (C 7 H 8 ) transported by a carrier gas selected from the group consisting of argon (Ar), nitrogen (N 2 ), helium (He) and hydrogen (H 2 ). 
   
   
       12 . The method of  claim 9 , wherein the etchant-resistive protection layer comprises amorphous silicon. 
   
   
       13 . The method of  claim 12 , wherein the etchant-resistive protection layer is deposited by vapor deposition using silane (SiH 4 ) gas. 
   
   
       14 . The method of  claim 9 , wherein the etchant-resistive protection layer is deposited to a thickness approximately in the range of 1-30 nanometers. 
   
   
       15 . The method of  claim 9 , wherein both the ARC layer and the etchant-resistive protection layer are formed by a technique selected from the group consisting of chemical vapor deposition, plasma-enhanced chemical vapor deposition, atmospheric-pressure chemical vapor deposition and physical vapor deposition. 
   
   
       16 . A method for fabricating a solar cell, comprising: providing, in a process chamber, a substrate having a light-receiving surface;
 flowing, in the process chamber, at least a first process gas and a second process gas to form an anti-reflective coating (ARC) layer above the light-receiving surface of the substrate; and   flowing, in the process chamber, at least the first process gas, but not the second process gas, to deposit an etchant-resistive protection layer above the ARC layer.   
   
   
       17 . The method of  claim 16 , wherein the etchant-resistive protection layer comprises amorphous silicon, and wherein the ARC layer comprises a material selected from the group consisting of silicon nitride, silicon oxy-nitride and carbon-doped silicon oxide. 
   
   
       18 . The method of  claim 17 , wherein the first process gas is silane (SiH 4 ) and the second process gas is ammonia (NH 3 ). 
   
   
       19 . The method of  claim 16 , wherein the etchant-resistive protection layer is deposited to a thickness approximately in the range of 1-30 nanometers. 
   
   
       20 . The method of  claim 16 , wherein both the ARC layer and the etchant-resistive protection layer are formed by a technique selected from the group consisting of chemical vapor deposition, plasma-enhanced chemical vapor deposition, atmospheric-pressure chemical vapor deposition and physical vapor deposition.