Semiconductor device and microwave process for its manufacture
AssigneeUnited Solar Systems Corporation
InventorsSubhendu Guha, Arindam Banerjee, Chi C. Yang
Life of this patent
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Abstract
Open circuit voltage of photovoltaic devices manufactured by a microwave deposition process is increased by disposing a bias wire in the microwave energized plasma and applying a positive voltage of approximately 100 volts to the wire during only a portion of the time in which the intrinsic semiconductor layer is being deposited.
Claims16
A method of making an improved semiconductor device of the type having a junction between a layer of intrinsic semiconductor material and a layer of doped semiconductor material, said method including the steps of:
- providing a deposition chamber;
- disposing a substrate in said chamber;
- disposing an energizable bias wire in said chamber proximate the substrate;
- introducing an intrinsic semiconductor precursor gas into the chamber;
- introducing microwave energy into the chamber, said energy operative to form a plasma from, and decompose, said intrinsic semiconductor precursor gas so as to deposit a layer of intrinsic semiconductor material on the substrate;
- energizing the bias wire with a positive voltage in excess of 50 volts during only a portion of the time the intrinsic semiconductor layer is being deposited;
- and,
- depositing a layer of doped semiconductor material on said layer of intrinsic semiconductor material.
A method of making an improved photovoltaic device of the type comprising a layer of intrinsic semiconductor material disposed between oppositely doped layers of semiconductor material, said method including the steps of:
- providing a deposition chamber, said chamber having a plasma region defined therein;
- disposing a bias wire in the plasma region;
- disposing a source of microwave energy, so as to introduce microwave energy into the plasma region of the deposition chamber;
- disposing a substrate having a first, doped semiconductor layer of a first conductivity type disposed upon at least a portion thereof in said plasma region;
- introducing an intrinsic semiconductor precursor gas into said chamber;
- introducing microwave energy into said chamber so as to energize said intrinsic semiconductor precursor gas so as to create a plasma therefrom which decomposes said intrinsic precursor gas and deposits a layer of intrinsic semiconductor material onto said first doped semiconductor layer;
- energizing said bias wire with voltage of at least +50 volts during a first portion of the time the microwaves are energizing the intrinsic semiconductor precursor gas and with a bias of less than +50 volts during a second portion of the time the microwaves are energizing the intrinsic semiconductor precursor gas;
- depositing a second doped semiconductor layer atop said layer of intrinsic semiconductor material, said second doped semiconductor layer being of opposite conductivity type to said first doped semiconductor layer.
Dependencies are inferred from the claim text.