Plasma deposition process with substrate temperature control
AssigneeUnited Solar Systems Corporation
InventorSubhendu Guha
Life of this patent
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Abstract
In a glow discharge deposition process for the preparation of hydrogenated, Group IV semiconductor alloys, the substrate is maintained at a temperature which is positively correlated with the deposition rate and which is high enough to impart sufficient kinetic energy to the layer to activate the removal of undesirable morphologies, but low enough to prevent degradation of the layer caused by the excessive loss of hydrogen.
Claims9
A method for the glow discharge deposition of a high quality layer of a hydrogenated, silicon containing semiconductor alloy material, including steps of:
- providing a deposition system having a plasma region defined therein, said system including a conduit for introducing a preselected process gas therein to and a source of electromagnetic energy for activating said process gas in said plasma region so as to form a plasma therefrom;
- supporting a substrate in said deposition system;
- introducing a process gas having hydrogen and at least silicon therein, into said system;
- maintaining the process gas at a process pressure which is less than atmospheric;
- inputting a preselected power level of electromagnetic energy into said process gas so as to create a plasma from, and decompose, the process gas into deposition species which deposit a layer of a hydrogenated, silicon containing, semiconductor alloy material on the substrate, at a deposition rate corresponding to said power level;
- and
- maintaining the substrate at a preselected temperature which has been determined to be positively correlated with the deposition rate and which is high enough to impart sufficient kinetic energy to the layer to activate the removal of undesirable morphologies therefrom, but low enough to prevent degradation of the layer caused by loss of hydrogen.
In a method for the manufacture of a photovoltaic device of the type including an intrinsic layer of a hydrogenated, silicon containing semiconductor material interposed between oppositely doped layers of semiconductor material, wherein said intrinsic layer is deposited by a glow discharge deposition process which comprises:
- providing a deposition system having a plasma region defined therein, said system including means for introducing a preselected process gas thereinto and a source of electromagnetic energy for activating the process gas in the plasma region to form a plasma therefrom;
- supporting a substrate in the deposition system;
- introducing a process gas including hydrogen and at least silicon therein, into said system;
- maintaining the process gas at a process pressure which is less than atmospheric;
- inputting a preselected power level of electromagnetic energy into the process gas so as to create a plasma from, and decompose, the process gas into deposition species which deposit a layer of a hydrogenated, silicon containing, semiconductor alloy material on the substrate, at a deposition rate corresponding to said power level, wherein the improvement comprises in combination:
- maintaining the substrate at a preselected temperature which has been determined to be positively correlated with the deposition rate and which is high enough to impart sufficient kinetic energy to the layer to activate she removal of undesirable morphologies therefrom, but low enough to prevent degradation of the layer caused by loss of hydrogen.
Dependencies are inferred from the claim text.