Methods of Building Crystalline Silicon Solar Cells for Use in Combinatorial Screening

Abstract

Embodiments of the current invention describe methods of forming different types of crystalline silicon based solar cells that can be combinatorially varied and evaluated. Examples of these different types of solar cells include front and back contact silicon based solar cells, all-back contact solar cells and selective emitter solar cells. These methodologies all incorporate the formation of site-isolated regions using a combinatorial processing tool and the use of these site-isolated regions to form the solar cell area. Therefore, multiple solar cells may be rapidly formed on a single crystalline silicon substrate for use in combinatorial methodologies. Any of the individual processes of the methods described may be varied combinatorially to test varied process conditions or materials.

What is claimed: 
     
         1 . A crystalline silicon solar cell test substrate, comprising:
 a diffusion barrier material deposited onto a frontside and a backside of a crystalline silicon substrate;   a plurality of site-isolated regions defined on the frontside of the crystalline silicon substrate, wherein the site-isolated regions are defined by etching regions of the diffusion barrier material to expose regions of crystalline silicon, and wherein the exposed regions of crystalline silicon are textured after the etching of the diffusion barrier material, and wherein the exposed regions of crystalline silicon are doped with an n-type dopant after the texturing of the exposed regions of crystalline silicon;   a passivation layer formed over the site-isolated regions;   an electrical contact formed to the doped exposed regions of crystalline silicon within each of the site-isolated regions; and   a plurality of electrical contacts formed to the backside of the crystalline silicon substrate, wherein at least one electrical contact formed to the backside of the crystalline silicon substrate is aligned with one of the site-isolated regions defined on the frontside of the crystalline silicon substrate.   
     
     
         2 . The silicon solar cell test substrate of  claim 1 , wherein the diffusion barrier material comprises one of silicon nitride or silicon dioxide. 
     
     
         3 . The silicon solar cell test substrate of  claim 1 , wherein the n-type dopant comprises phosphorous. 
     
     
         4 . The silicon solar cell test substrate of  claim 1 , wherein the passivation layer comprises one of silicon nitride or silicon dioxide. 
     
     
         5 . The silicon solar cell test substrate of  claim 1 , further comprising electrical lines and contact points to allow testing of solar cells formed within each site-isolated region. 
     
     
         6 . A crystalline silicon solar cell test substrate, comprising:
 a diffusion barrier material deposited onto a frontside of a crystalline silicon substrate;   a plurality of site-isolated regions defined on the frontside of the crystalline silicon substrate, wherein the site-isolated regions are defined by etching regions of the diffusion barrier material to expose regions of crystalline silicon, and wherein the exposed regions of crystalline silicon are textured after the etching of the diffusion barrier material, and wherein the exposed regions of crystalline silicon are doped with an n-type dopant after the texturing of the exposed regions of crystalline silicon;   a passivation layer formed over the site-isolated regions defined on the frontside of the crystalline silicon substrate;   a plurality of alternating n-doped and p-doped regions defined on the backside of the crystalline silicon substrate, wherein the alternating n-doped and p-doped regions are defined by photolithography, and wherein at least one n-doped region and at least one p-doped region are aligned with each of the site-isolated regions defined on the frontside of the crystalline silicon substrate;   a passivation layer formed over the plurality of alternating n-doped and p-doped regions defined on the backside of the crystalline silicon substrate; and   an electrical contact formed to each of the plurality of alternating n-doped and p-doped regions defined on the backside of the crystalline silicon substrate.   
     
     
         7 . The silicon solar cell test substrate of  claim 6 , wherein the diffusion barrier material comprises one of silicon nitride or silicon dioxide. 
     
     
         8 . The silicon solar cell test substrate of  claim 6 , wherein the n-type dopant comprises phosphorous. 
     
     
         9 . The silicon solar cell test substrate of  claim 6 , wherein the passivation layer formed over the site-isolated regions defined on the frontside of the crystalline silicon substrate comprises one of silicon nitride or silicon dioxide. 
     
     
         10 . The silicon solar cell test substrate of  claim 6 , wherein the passivation layer formed over the plurality of alternating n-doped and p-doped regions defined on the backside of the crystalline silicon substrate comprises one of silicon nitride or silicon dioxide. 
     
     
         11 . The silicon solar cell test substrate of  claim 6 , further comprising electrical lines and contact points to allow testing of solar cells formed within each site-isolated region. 
     
     
         12 . A crystalline silicon solar cell test substrate, comprising:
 a diffusion barrier material deposited onto a frontside and a backside of a crystalline silicon substrate;   a plurality of site-isolated regions defined on the frontside of the crystalline silicon substrate, wherein the site-isolated regions are defined by etching regions of the diffusion barrier material to expose regions of crystalline silicon, and wherein the exposed regions of crystalline silicon are textured after the etching of the diffusion barrier material, and wherein the exposed regions of crystalline silicon are lightly doped with an n-type dopant after the texturing of the exposed regions of crystalline silicon, and wherein a portion of each site-isolated region is heavily doped with an n-type dopant after the lightly doping of the exposed regions of crystalline silicon;   a passivation layer formed over the site-isolated regions;   an electrical contact formed to the heavily doped exposed regions of crystalline silicon within each of the site-isolated regions; and   a plurality of electrical contacts formed to the backside of the crystalline silicon substrate, wherein at least one electrical contact formed to the backside of the crystalline silicon substrate is aligned with one of the site-isolated regions defined on the frontside of the crystalline silicon substrate.   
     
     
         13 . The silicon solar cell test substrate of  claim 12 , wherein the diffusion barrier material comprises one of silicon nitride or silicon dioxide. 
     
     
         14 . The silicon solar cell test substrate of  claim 12 , wherein the n-type dopant comprises phosphorous. 
     
     
         15 . The silicon solar cell test substrate of  claim 12 , wherein the passivation layer comprises one of silicon nitride or silicon dioxide. 
     
     
         16 . The silicon solar cell test substrate of  claim 12 , further comprising electrical lines and contact points to allow testing of solar cells formed within each site-isolated region. 
     
     
         17 . The silicon solar cell test substrate of  claim 12 , wherein the lightly doped exposed regions of crystalline silicon have a sheet resistance of approximately 70-100 ohms/square. 
     
     
         18 . The silicon solar cell test substrate of  claim 12 , wherein the heavily doped exposed regions of crystalline silicon have a sheet resistance of approximately 20-30 ohms/square.