Silicon structure, method for producing the same, and solar battery using the silicon structure

Abstract

A silicon structure having little solar light beam reflection, which is suitable for a solar battery. On the entire surface of a quartz substrate, Mo is deposited at a thickness of approximately 1 μm to form a lower electrode. On the entire surface of the lower electrode, a p type silicon structure having a thickness of 30 to 40 μm comprising an aggregate of a plurality of columnar silicon members mainly comprising silicon and having random orientations is formed via a film mainly comprising silicon, using Si 2 Cl 6 mixed with BCl 3 . On the surface of the p type silicon structure, P is diffused by a thermal diffusion method using POCl 3 to form an n type region at the periphery of the columnar silicon members. On the entire surface of the p type silicon structure, a transparent electrode comprising indium-tin oxide having a thickness of 30 to 40 μm is formed, and an upper electrode comprising Al having a thickness of approximately 1 μm is formed on the transparent electrode.

What is claimed is:  
     
         1 . A silicon structure comprising an aggregate of a plurality of columnar silicon members mainly comprising silicon and having random orientations.  
     
     
         2 . A substrate having a first surface on which the silicon structure of  claim 1  is formed via a vilm mainly comprising silicon.  
     
     
         3 . The silicon structure according to  claim 1 , wherein the diameter of the columnar silicon members is from 0.1 to 10 μm.  
     
     
         4 . The silicon structure according to  claim 1 , wherein the periphery of the columnar silicon members is amorphous and the center portion of the columnar silicon members is polycrystalline.  
     
     
         5 . A method for producing a silicon structure comprising an aggregate of a plurality of columnar silicon members mainly comprising silicon and having random orientations, wherein an atomized or vaporized silicon material containing chlorine is introduced to a heated substrate with an oxygen gas.  
     
     
         6 . The method according to  claim 5 , wherein the silicon material containing chlorine is Si 2 Cl 6 .  
     
     
         7 . The method according to  claim 6 , wherein an n type or p type silicon structure is formed by using a liquid material prepared by mixing PCl 3  or BCl 3  into the Si 2 Cl 6 .  
     
     
         8 . The method according to  claim 5 , wherein the oxygen gas is introduced so as to provide an oxygen content in the vicinity of the center of the columnar siliconmembers of 3% or less.  
     
     
         9 . An apparatus for producing a silicon structure comprising an aggregate of a plurality of columnar silicon members mainly comprising silicon and having random orientations on a substrate, the apparatus comprising: 
 a chamber;    means to supply an atomized or vaporized liquid material comprising silicon and oxygen gas to the chamber;    a support for a substrate to be treated by the apparatus;    a heater for a substrate to be treated by the apparatus; and    a filter having an area that is at least as large as the area of a substrate to be treated by the apparatus, through which the atomized or vaporized liquid material and oxygen gas are introduced to a substrate to be treated by the apparatus.    
     
     
         10 . The apparatus according to  claim 9 , wherein the filter comprises a stainless steel fiber.  
     
     
         11 . The apparatus according to  claim 9 , wherein the pore size of the filter is from 1 to 30 μm.  
     
     
         12 . A solar battery comprising a semiconductor layer to generate an electron-hole pair by a light radiation, wherein the semiconductor layer comprises a silicon structure comprising an aggregate of a plurality of columnar silicon members mainly comprising silicon and having random orientations.  
     
     
         13 . The solar battery according to  claim 12 , further comprising a substrate, on which the silicon structure is formed via a film mainly comprising silicon.  
     
     
         14 . The solar battery according to  claim 12 , wherein the diameter of the columnar silicon members is 0.1 to 10 μm.  
     
     
         15 . The solar battery according to  claim 12 , wherein the peripheral portion of the columnar silicon members is amorphous and the center portion of the columnar silicon members is polycrystalline.  
     
     
         16 . The solar battery according to  claim 12 , wherein the silicon structure is formed on the surface of the side of the semiconductor layer at which a light beam enters.  
     
     
         17 . The solar battery according to  claim 12 , wherein a pn junction is formed inside the columnar silicon members