Method for forming solar cell with selective emitters

Abstract

A method for forming a solar cell with selective emitters is provided. The method for forming a solar cell with selective emitters includes providing a substrate; forming a first texture structure on a first surface of the substrate; performing a doping process to the first surface of the substrate to form a first doping region in the substrate; forming a pattered barrier layer in a second region on the first surface of the substrate, wherein another portion of the substrate in a first region is exposed; performing a second texture etching process to etch the first region of the substrate uncovered by the patterned barrier layer; removing the patterned barrier layer; and forming an electrode on the second region of the substrate.

What is claimed is: 
     
         1 . A method for forming a solar cell with selective emitters, comprising:
 providing a substrate;   forming a first texture structure on a first surface of the substrate;   performing a doping process to the first surface of the substrate to form a first doping region in the substrate;   forming a pattered barrier layer in a second region on the first surface of the substrate, wherein another portion of the substrate in a first region is exposed;   performing a second texture etching process to etch the first region of the substrate uncovered by the patterned barrier layer;   removing the patterned barrier layer; and   forming an electrode on the second region of the substrate.   
     
     
         2 . The method for forming a solar cell with selective emitters as claimed in  claim 1 , wherein the second texture etching process treats the substrate surface in the first region to a second doping region, and doping concentration of the second doping region is lower than that of the first doping region. 
     
     
         3 . The method for forming a solar cell with selective emitters as claimed in  claim 1 , wherein the second texture etching process comprises:
 performing an electroless treatment; and   performing selective oxidizing and removing steps.   
     
     
         4 . The method for forming a solar cell with selective emitter as claimed in  claim 3 , wherein N 2 S 2 O 8  is used as an oxidizer, and AgNO 3 , H 2 O 2  or NaOH are used as catalytic agents in the electroless treatment process and the selective oxidizing products removing steps is performed in a solution containing HF and H 2 O 2 . 
     
     
         5 . The method for forming a solar cell with selective emitter as claimed in  claim 1 , further comprising forming an anti-reflective layer on the substrate surface before forming the electrode. 
     
     
         6 . The method for forming a solar cell with selective emitter as claimed in  claim 5 , wherein the pattered barrier layer and the anti-reflective layer are formed of silicon oxide silicon nitride or aluminum oxide. 
     
     
         7 . The method for forming a solar cell with selective emitter as claimed in  claim 5 , wherein the anti-reflective layer is formed by plasma enhanced chemical vapor deposition (PECVD). 
     
     
         8 . The method for forming a solar cell with selective emitter as claimed in  claim 1 , wherein the doping process dopes phosphorous or boron. 
     
     
         9 . The method for forming a solar cell with selective emitters as claimed in  claim 1 , wherein the second texture etching process treats the substrate surface in the first region to a second doping region, wherein sheet resistance of the first doping region is lower than that of the second doping region. 
     
     
         10 . The method for forming a solar cell with selective emitters as claimed in  claim 1 , wherein the second texture etching process removes about 50 nm-70 nm of the substrate surface in the first region to form a second doping region. 
     
     
         11 . The method for forming a solar cell with selective emitters as claimed in  claim 1 , wherein duration of the second texture etching process is about 60 sec. 
     
     
         12 . The method for forming a solar cell with selective emitters as claimed in  claim 1 , wherein the first texture structure is formed by alkaline etching process. 
     
     
         13 . The method for forming a solar cell with selective emitters as claimed in  claim 1 , wherein the first texture structure is formed by acid etching process. 
     
     
         14 . The solar cell with selective emitters as claimed in  claim 1 , wherein the pattered barrier layer is formed by screen printing.