Template for three-dimensional thin-film solar cell manufacturing and methods of use

Abstract

A template 100 for three-dimensional thin-film solar cell substrate formation for use in three-dimensional thin-film solar cells. The template 100 comprises a substrate which comprises a plurality of posts 102 and a plurality of trenches 104 between said plurality of posts 102. The template 100 forms an environment for three-dimensional thin-film solar cell substrate formation.

1 . A solar panel fabrication method, comprising the steps of:
 simultaneously thermally smoothing surface of porous silicon layers formed on a plurality of wafers attached to a susceptor;   depositing a plurality of n-type and p-type silicon layers simultaneously on all said thermally smoothed porous silicon layers in the wafers attached to the susceptor, thereby creating photovoltaic (PV) cells on the surfaces of each of said wafers in said multiplicity of wafers; and   simultaneously forming in all of the wafers at least some of the contacts to the n-type and p-type layers in each of the wafers.   
     
     
         2 . The method of  claim 1 , further comprising the step of simultaneously forming the porous silicon layers on the surfaces of wafers attached to the susceptor. 
     
     
         3 . The method of  claim 1 , wherein the step of simultaneously forming the porous silicon layer comprises anodization in a liquid electrolyte. 
     
     
         4 . The method of  claim 1 , wherein the contact forming step includes depositing a patterned contact precursor on all of the wafers attached to the susceptor and further comprising the steps of:
 depositing a precursor of a handling layer on the upper surface of all the wafer attached to the susceptor; and   simultaneously heating all of said wafers attached to the susceptor to sinter said screen printed contacts to at least some of n-type and p-type layers, and to thermally convert said handling layer precursor into handling layers on all said wafers, the handling layer not bridging neighboring ones of the PV cells.   
     
     
         5 . The solar panel fabrication method of  claim 1 , further comprising the steps of:
 depositing a glue layer across all said wafers in said multiplicity of wafers, the glue layer bridging neighboring ones of the solar cells;   thermally bonding said glue layer to said multiplicity of wafers;   exfoliating said PV cells from each wafer in said multiplicity of wafers attached together by the glue layer; and   then removing the remnants of said porous silicon layer from said PV cells.   
     
     
         6 . The solar panel fabrication method of  claim 5 , further comprising the steps of:
 simultaneously texture etching the fronts of all said wafers;   simultaneously depositing an anti-reflective coating on the fronts of all said wafers;   simultaneously depositing metal on the back sides of all said wafers; and   simultaneously depositing strengthening layers on the back sides of all said wafers.   
     
     
         7 . A solar panel fabrication method, comprising the steps of:
 forming porous silicon layers on each of a multiplicity of silicon wafers;   attaching said multiplicity of wafers to a susceptor;   simultaneously thermally smoothing the surfaces of all said porous silicon layers;   depositing a plurality of n-type and p-type silicon layers simultaneously on said thermally smoothed porous silicon layers in all of the multiplicity of wafers, thereby creating photovoltaic (PV) cells on the surfaces of each of said wafers in said multiplicity of wafers; and   simultaneously forming at least some of the contacts to the n-type and p-type layers.   
     
     
         8 . The method of  claim 7 , wherein the step of forming at least some of the contacts includes screen printing. 
     
     
         9 . The solar panel fabrication method of  claim 7 , further comprising the steps of:
 depositing a precursor for a handling layer on the upper surface of all said wafers; and   simultaneously heating all said wafers to thermally convert said handling layer precursor into handling layers on all said wafers, wherein the handling layer does not bridge neighboring ones of the PV cells.   
     
     
         10 . The solar panel fabrication method of  claim 8 , further comprising the step of attaching metal stringers to all said contacts. 
     
     
         11 . The solar panel fabrication method of  claim 8 , further comprising the steps of:
 depositing a glue layer across all said wafers in said multiplicity of wafers;   thermally bonding said glue layer to said multiplicity of wafers; and   exfoliating said PV cells from each wafer in said multiplicity of wafers.   
     
     
         12 . The solar panel fabrication method of  claim 11 , further comprising the steps performed after the exfoliating step of:
 simultaneously texture etching the fronts of all said wafers;   simultaneously depositing an antireflective coating on the fronts of all said wafers;   simultaneously depositing metal on the back sides of all said wafers; and   simultaneously depositing strengthening layers on the back sides of all said wafers.   
     
     
         13 . A solar cell fabrication method, comprising the steps of:
 mounting on a support in a two-dimension array a plurality of silicon wafers including respective separation layers;   simultaneously depositing on the wafers by chemical vapor deposition a solar cell structure including p-type and n-type layers; and   separating as a unit the solar cell structure attached to all the wafers by a peeling motion from one side to the other of the array.   
     
     
         14 . The method of  claim 13 , wherein the separation layers are porous silicon layers formed in the wafers by anodization thereof. 
     
     
         15 . A method for simultaneously anodically etching a multiplicity of wafers affixed to a substrate, comprising the steps of:
 attaching a multiplicity of wafers to a support structure;   providing an etching chamber with anode and cathode plates, each electrically attached to a dc power supply;   filling said etching chamber with an etchant solution;   immersing said support structure in said etch chamber with a fluid seal between the edges of said support structure and the internal walls of said etching chamber;   impressing a negative DC bias to said cathode plate; and   impressing a positive DC bias to said anode plate.   
     
     
         16 . An anodic etching system for simultaneously etching a multiplicity of wafers attached to a support structure, comprising:
 an etching tank for containing therein an etchant solution;   a DC power supply;   a cathode plate immersible in said etchant solution and mounted near one end of said etching chamber;   an anode plate immersible in said etchant solution and mounted at the opposite end of said etching chamber from said cathode plate;   a multiplicity of support plates serially arranged between the cathode and anode plates and fluid sealed to side walls of the tank, each configured to support one or more wafers affixed to said support plate, thereby providing contact between both the front and back surfaces of said wafers to said etchant solution.   
     
     
         17 . The system of  claim 16 , wherein the support plates contains a plurality of windows therethrough formed between ribs therein, each window exposing a portion of one of a plurality of the wafers and the ribs being fluid sealed to the wafers. 
     
     
         18 . A method for exfoliating a multiplicity of photovoltaic (PV) cells covered with an continuous layer and arranged in at least a one-dimensional array, wherein each of said PV cells is formed on the surface of a porous silicon layer etched on the surface of one of a plurality of mother wafers in an array of mother wafers affixed to an upper surface of a support member, comprising the steps of:
 providing a plurality of independently vertically movable clamps in a linear array, wherein each of said clamps has a clamping surface juxtaposable to respective ones of the PV cells across a respective layer bonded to all of the PV cells; and   sequentially pulling through said clamps each of the array of solar cells in a sequence extending in a first direction from one side to the other side of the one-dimensional array.   
     
     
         19 . The method of  claim 18  wherein at least two of said clamps are juxtaposable to each respective ones of the solar cells. 
     
     
         20 . The method of  claim 18 , wherein the at least one-dimensional array is a two-dimensional array extending along the first direction and a second direction perpendicular thereto and wherein each of the clamps has a clamping surface juxtaposable to a plurality of PV cells arranged along the second direction.