Thin film growth using two part metal solvent
AssigneeUnisearch Limited
InventorsMartin A. Green, Stuart R. Wenham
Life of this patent
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Abstract
A method of coating a material surface with thin film silicon comprises dissolving silicon in a metal solvent to form a solution and subsequently deposited the dissolved silicon from the solution by controlling the temperature of the solution and thereby depositing a layer of silicon onto the material surface. The metal solvent is preferably a mixture of gold and a metal or metals which either have a melting point below the deposition temperature range or which form a eutectic with gold and have a eutectic temperature below the deposition temperature range. The temperature of the solution is controlled so that the silicon becomes super saturated in the solution and is deposited out of solution onto the material surface.
Claims27
A solution growth method for depositing a thin film semiconductor coating on a supporting substrate, the method comprising dissolving said semiconductor in a molten metal solvent to form a solution of said metal solvent and dissolved semiconductor, subsequently precipitating said semiconductor from the solution onto a supporting substrate, characterized in that said solvent is a mixture of:
- a first metal which forms a eutectic with said semiconductor having a eutectic temperature below the melting point of said first metal when substantially pure;
- and
- a second metal or mixture of second metals which, in their substantially pure state, have a melting point below the eutectic temperature of said first metal and said semiconductor and said second metal or mixture of second metals being substantially completely miscible with said first metal.
A method of coating a glass sheet with thin film silicon comprising the steps of:
- dissolving silicon in a solution of gold and tin wherein the gold and tin are present in a ratio of from 7:3 to 4:1 (gold:tin by weight to form a solution of silicon, gold and tin, the dissolving being carried out at a first temperature below about 600.degree. C. until the silicon reaches approximately the saturation level of silicon in the solution;
- wetting a surface of the glass sheet by contacting the solution with the sheet and maintaining the surface in contact with the solution;
- precipitating silicon from the solution onto the surface by lowering the temperature of the solution;
- and
- controlling the rate of growth and final thickness of the silicon film by controlling the rate of change of the solution temperature and the length of time the surface remains in contact with the solution.
A solution growth method for depositing a thin film semiconductor coating on a supporting substrate, the method comprising
- dissolving said semiconductor in a molten metal solvent to form a solution of said metal solvent and dissolved semiconductor and subsequently precipitating said semiconductor from the solution onto a supporting substrate, characterized in that said solvent in a mixture of:
- a first metal which forms a eutectic with said semiconductor, the first metal being selected from the group consisting of Au, Al, As, Bi, Cd, Cu, Ga, Hg, In, Ni, Pb, Pd, Sb, Sn, Tl and Zn;
- and
- a second metal or mixture of second metals which, in their substantially pure state, have a melting point below the eutectic temperature of said first metal and said semiconductor and said second metal or mixture of second metals being substantially completely miscible with said first metal.
Dependencies are inferred from the claim text.