Method for releasing a thin-film substrate
First Claim
1. A method for fabrication of a thin-film crystalline semiconductor substrate by releasing it from a semiconductor template through the use of a sacrificial porous semiconductor seed and release layer, the method comprising:
- forming a porous semiconductor layer on a semiconductor template measuring at least 200 mm×
200 mm, said porous semiconductor layer substantially conformal to said semiconductor template;
forming a thin-film crystalline semiconductor substrate on said porous semiconductor layer, said thin-film semiconductor substrate substantially conformal to said porous semiconductor layer; and
selectively and chemically wet etching said porous semiconductor layer with a high-etch-selectivity wet etchant, said wet etchant solution comprising dilute TMAH or KOH or NaOH;
releasing said thin-film semiconductor substrate as a free-standing, self-supporting semiconductor substrate from said semiconductor template via selective wet etching of said porous semiconductor layer.
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Abstract
The present disclosure relates to methods for selectively etching a porous semiconductor layer to separate a thin-film semiconductor substrate (TFSS) having planar or three-dimensional features from a corresponding semiconductor template. The method involves forming a conformal sacrificial porous semiconductor layer on a template. Next, a conformal thin film silicon substrate is formed on top of the porous silicon layer. The middle porous silicon layer is then selectively etched to separate the TFSS and semiconductor template. The disclosed advanced etching chemistries and etching methods achieve selective etching with minimal damage to the TFSS and template.
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Citations
20 Claims
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1. A method for fabrication of a thin-film crystalline semiconductor substrate by releasing it from a semiconductor template through the use of a sacrificial porous semiconductor seed and release layer, the method comprising:
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forming a porous semiconductor layer on a semiconductor template measuring at least 200 mm×
200 mm, said porous semiconductor layer substantially conformal to said semiconductor template;forming a thin-film crystalline semiconductor substrate on said porous semiconductor layer, said thin-film semiconductor substrate substantially conformal to said porous semiconductor layer; and selectively and chemically wet etching said porous semiconductor layer with a high-etch-selectivity wet etchant, said wet etchant solution comprising dilute TMAH or KOH or NaOH; releasing said thin-film semiconductor substrate as a free-standing, self-supporting semiconductor substrate from said semiconductor template via selective wet etching of said porous semiconductor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification