Low-cost solar cells and methods for fabricating low cost substrates for solar cells
AssigneeSunpreme, Ltd.
InventorsAshok Sinha, Wen Ma
Life of this patent
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Abstract
Substrates for solar cells are prepared by etching a plurality of metallurgical grade wafers; depositing aluminum layer on backside of each wafer; depositing a layer of hydrogenated silicon nitride on front surface of each wafer; annealing the wafers at elevated temperature; removing the hydrogenated silicon nitride without disturbing the aluminum layer. A solar cell is then fabricated on the front surface of the wafer while the aluminum remain to serve as the back contact of the cell.
Claims20
A method for preparing substrates using metallurgical grade silicon, comprising:
- obtaining wafer consisting of metal grade silicon;
- performing conditioning etch on the wafer;
- depositing a sacrificial layer on front surface of the wafer;
- depositing metallization layer on backside of the wafer;
- annealing the wafer at elevated temperature;
- and,
- removing the sacrificial layer without disturbing the metallization layer.
A method for preparing substrates for solar cells using metallurgical grade silicon, comprising:
- obtaining wafer consisting of metal grade silicon;
- performing saw damage removal etch on the wafer;
- performing cleaning etch on the wafer;
- depositing a hydrogenated sacrificial layer on front surface of the wafer;
- depositing metallization layer on backside of the wafer at first elevated temperature;
- annealing the wafer at a second elevated temperature higher than the first elevated temperature;
- and,
- removing the hydrogenated sacrificial layer without disturbing the metallization layer.
Dependencies are inferred from the claim text.