Back contact solar cell and fabrication method thereof

Abstract

The present invention discloses a back contact solar cell. The back contact solar cell includes a semiconductor substrate having a front surface and a rear surface; a first conductive type semiconductor region having a first conductive type and a second conductive type semiconductor region having a second conductive type at an interval on the rear surface of the semiconductor substrate. Furthermore, the rear surface of the semiconductor substrate has a texturing structure at the interval between the first conductive type semiconductor region and the second conductive type semiconductor region.

What is claimed is: 
     
         1 . A method of making a back contact solar cell, the method comprising:
 forming an oxide layer on a rear surface of a semiconductor substrate;   forming a first conductive type semiconductor region by doping a first dopant material of a first conductive type;   forming a second conductive type semiconductor region by doping a second dopant material of a second conductive type;   patterning the oxide layer on the rear surface of the semiconductor substrate to locally remove the oxide layer on the rear surface at a first location to form a first exposed portion of the semiconductor substrate to form a first contact between the first conductive type semiconductor region and a first electrode, and at a second location to form a second exposed portion of the semiconductor substrate to form a second contact between the second conductive type semiconductor region and a second electrode; and   forming the first electrode at the first exposed portion and the second electrode at the second exposed portion.   
     
     
         2 . The method according to  claim 1 , wherein the first conductive type is an n-type, and
 wherein, in the forming the first conductive type semiconductor region, POCl 3  is used as a source of the first dopant material.   
     
     
         3 . The method according to  claim 1 , further comprising:
 forming an oxide layer on a front surface of the semiconductor substrate.   
     
     
         4 . The method according to  claim 1 , wherein the patterning is performed using an irradiated laser light. 
     
     
         5 . The method according to  claim 1 , wherein the first dopant material is an n-type material and the second dopant material is a p-type material. 
     
     
         6 . The method according to  claim 1 , wherein the forming of oxide layer is performed as one of
 a rapid thermal oxidation (RTO) method performed inside a furnace for rapid thermal processing (RTP); and   a sputtering method using silicon oxide as a target material.   
     
     
         7 . The method according to  claim 1 , wherein a portion of the oxide layer remains on the rear surface of the semiconductor substrate. 
     
     
         8 . The method according to  claim 1 , wherein the first conductive type semiconductor region and the second conductive type semiconductor region is disposed with an interval on the rear surface of the semiconductor substrate. 
     
     
         9 . The method according to  claim 8 , wherein the rear surface of the semiconductor substrate has a texturing structure at the interval between the first conductive type semiconductor region and the second conductive type semiconductor region. 
     
     
         10 . The method according to  claim 9 , wherein the rear surface of the semiconductor substrate further has a portion having a flat surface, and
 the flat surface is between the first contact and the texturing structure, the second contact and the texturing structure, or both.   
     
     
         11 . The method according to  claim 10 , wherein a width of a portion of the first electrode is greater than a width of the first conductive type semiconductor region, or a width of a portion of the second electrode is greater than a width of the second conductive type semiconductor region. 
     
     
         12 . The method according to  claim 9 , wherein the rear surface of the semiconductor substrate has the texturing structure locally to correspond only to the interval between the first conductive type semiconductor region and the second conductive type semiconductor region. 
     
     
         13 . The method according to  claim 9 , wherein the texturing structure is not formed on at portions of the rear surface of the semiconductor substrate corresponding to the first conductive type semiconductor region and the second conductive type semiconductor region. 
     
     
         14 . The method according to  claim 1 , wherein the oxide layer is interposed between the first conductive type semiconductor region and the second conductive type semiconductor region. 
     
     
         15 . The method according to  claim 9 , wherein the oxide layer is formed on the rear surface of the semiconductor substrate at an interval between the first conductive type semiconductor region and the second conductive type semiconductor region, and
 the oxide layer has a corresponding texturing structure to the texturing structure of the semiconductor substrate.   
     
     
         16 . A method of making a back contact solar cell, the method comprising:
 forming an oxide layer on a rear surface of a semiconductor substrate;   removing at least one portion of the oxide layer by using a laser to expose the semiconductor substrate;   providing POCl 3  to the exposed portion of the semiconductor substrate;   providing a first dopant material to a first portion on the semiconductor substrate;   providing a second dopant material to a second portion on the semiconductor substrate; and   forming a first electrode on the first portion and a second electrode on the second portion.   
     
     
         17 . The method of  claim 16 , further comprising forming a first conductive type semiconductor region on the first portion and forming a second conductive type semiconductor region on the second portion. 
     
     
         18 . The method of  claim 17 , wherein the forming of the first conductive type semiconductor region and the forming of the second conductive type semiconductor region are performed by thermally diffusing the first and second dopant materials respectively into the first and second conductive type semiconductor regions. 
     
     
         19 . The method of  claim 17 , wherein the first conductive type semiconductor region is an n-type and the second conductive type semiconductor region is a p-type. 
     
     
         20 . The method according to  claim 16 , wherein a portion of the oxide layer remains on the rear surface of the semiconductor substrate.