Solar cell and method for manufacturing the same

Abstract

A solar cell includes a substrate; a first passivation layer on a first surface of the substrate; a first field region on the first surface of the substrate; an anti-reflection layer on the first passivation layer; a second passivation layer on a second surface of the substrate; an emitter region on the second passivation layer, the emitter region forming a p-n junction and a hetero-junction junction with the substrate; a second field region on the second passivation layer, the second field region forming a hetero-junction with the substrate; a first electrode contacted to the emitter region; a second electrode contacted to the second field region; a spacing between the emitter region and the second field region; and a third passivation layer on the second surface of the substrate at the spacing.

What is claimed is: 
     
         1 . A solar cell, comprising:
 a substrate including first impurities having a first conductive type;   a first passivation layer that is positioned on a first surface of the substrate;   a first field region positioned on the first surface of the substrate, and containing second impurities having the first conductive type;   an anti-reflection layer positioned on the first passivation layer;   a second passivation layer directly positioned on a second surface of the substrate opposite the first surface of the substrate, and having a thickness of lnm to lOnm;   an emitter region that contains third impurities having a second conductive type opposite the first conductive type, and is positioned on the second passivation layer, the emitter region forming a p-n junction and a hetero-junction junction with the substrate;   a second field region that is positioned on the second passivation layer, the second field region having the same conductive type as the first field region, and the second field region forming a hetero-junction with the substrate;   a first electrode directly contacted to the emitter region;   a second electrode directly contacted to the second field region;   a spacing between the emitter region and the second field region to physically separate the emitter region and the second field region; and   a third passivation layer directly positioned on the second surface of the substrate at the spacing and having a thickness greater than the thickness of the second passivation layer,   wherein the second passivation layer transfers a carrier to the emitter region and the second field region, and   wherein the third passivation layer is formed of an insulating material.   
     
     
         2 . The solar cell of  claim 1 , wherein a crystallinity of the substrate is different from that of at least one of the emitter region and the second field region. 
     
     
         3 . The solar cell of  claim 2 , wherein the substrate is formed of a crystalline semiconductor, and
 wherein at least one of the emitter region and the second field region is formed of an amorphous semiconductor.   
     
     
         4 . The solar cell of  claim 1 , wherein the second passivation layer includes an insulating portion and a conductive portion. 
     
     
         5 . The solar cell of  claim 1 , wherein the second passivation layer is formed of an intrinsic amorphous semiconductor layer. 
     
     
         6 . The solar cell of  claim 5 , wherein the second passivation layer is formed of a material including Si. 
     
     
         7 . The solar cell of  claim 1 , wherein the third passivation layer is formed of at least one of SiOx and SiNx. 
     
     
         8 . The solar cell of  claim 1 , wherein a crystallinity of the substrate is different from a crystallinity of the emitter region and a crystallinity of the second field region, and the crystallinity of the emitter region is equal to the crystallinity of the second field region. 
     
     
         9 . The solar cell of  claim 1 , wherein each of the first passivation layer, the first field region and the anti-reflection layer are formed on a textured surface of the substrate. 
     
     
         10 . The solar cell of  claim 1 , wherein a thickness of the first passivation layer is 2 nm to 20 nm. 
     
     
         11 . The solar cell of  claim 1 , wherein the anti-reflection layer is formed of at least one of SiOx and SiNx. 
     
     
         12 . The solar cell of  claim 1 , wherein the anti-reflection layer is formed of a transparent metal oxide. 
     
     
         13 . The solar cell of  claim 1 , wherein the anti-reflection layer has a single-layered structure or a multi-layered structure. 
     
     
         14 . The solar cell of  claim 1 , wherein the second field region is more heavily doped with impurities of the same conductive type as the substrate than the substrate. 
     
     
         15 . The solar cell of  claim 1 , wherein the emitter region and the second field region are parallel to each other while interposing the spacing. 
     
     
         16 . The solar cell of  claim 1 , wherein the first electrode and the second electrode are formed of at least one conductive material selected from the group consisting of nickel (Ni), copper (Cu), silver (Ag), aluminum (Al), tin (Sn), zinc (Zn), indium (In), titanium (Ti), gold (Au), and a combination thereof. 
     
     
         17 . The solar cell of  claim 1 , wherein the first electrode and the second electrode reflect light passing through the substrate. 
     
     
         18 . The solar cell of  claim 1 , wherein the substrate, the first field region and the second field region are doped with at least one of impurities of a group V element including phosphor (P), arsenic (As), and antimony (Sb), and the emitter region is doped with at least one of impurities of a group III element including boron (B), gallium (Ga), and indium (In).