Government of the United States of America, As Represented by the Secretary of Commerce

Midwest Research Institute

The United States of America As Represented by the United States

Matsushita Electric Works R&d Laboratory, Inc.

Alan C Gallagher

Archie Harvin Mahan

Edith C Molenbroek

Brent P Nelson

Eugene Iwaniczko

Yueqin Xu

Shin Ukegawa

Jeffrey C Carapella

A method of fabricating device quality, thin-film a-Si:H for use as semiconductor material in photovoltaic and other devices, comprising in any order; positioning a substrate in a vacuum chamber adjacent a plurality of heatable filaments with a spacing distance L between the substrate and the filaments; heating the filaments to a temperature that is high enough to obtain complete decomposition of silicohydride molecules that impinge said filaments into Si and H atomic species; providing a flow of silicohydride gas, or a mixture of silicohydride gas containing Si and H, in said vacuum chamber while maintaining a pressure P of said gas in said chamber, which, in combination with said spacing distance L, provides a P&times;L product in a range of 10-300 mT-cm to ensure that most of the Si atomic species react with silicohydride molecules in the gas before reaching the substrate, to thereby grow a a-Si:H film at a rate of at least 50 &angst;/sec.; and maintaining the substrate at a temperature that balances out-diffusion of H from the growing a-Si:H film with time needed for radical species containing Si and H to migrate to preferred bonding sites.

Deposition of device quality, low hydrogen content, hydrogenated amorphous silicon at high deposition rates

A method or producing hydrogenated amorphous silicon on a substrate, comprising the steps of: positioning the substrate in a deposition chamber at a distance of about 0.5 to 3.0 cm from a heatable filament in the deposition chamber; maintaining a pressure in said deposition chamber in the range of about 10 to 100 millitorr and pressure times substrate-filament spacing in the range of about 10 to 100 millitorr-cm, heating the filament to a temperature in the range of about 1,500 to 2,000.degree. C., and heating the substrate to a surface temperature in the range of about 280 to 475.degree. C.; and flowing silicohydride gas into the deposition chamber with said heated filament, decomposing said silicohydride gas into silicon and hydrogen atomic species and allowing products of gas reactions between said atomic species and the silicohydride gas to migrate to and deposit on said substrate while adjusting and maintaining said pressure times substrate-filament spacing in said deposition chamber at a value in said 10 to 100 millitorr range to produce statistically about 3 to 50 atomic collisions between the silicon and hydrogen atomic species migrating to said substrate and undecomposed molecules of the silane or other silicohydride gas in the deposition chamber.

Deposition of device quality, low hydrogen content, hydrogenated

The present invention is directed to a metal hydrides lamp and a fill for such a lamp. The lamp chamber includes a fill of at least one metal, a buffer gas, and hydrogen and/or deuterium. When energy is provided to the fill, metal combines with the hydrogen and/or deuterium to form a molecule at an excited energy level which emits visible light when the molecule moves to a ground state energy level. The lamp may be an electrode lamp, an electrodeless lamp, a microwave lamp, or any other power source capable of imparting energy into a fill contained within a lamp chamber.

Metal hydrides lamp and fill for the same

A high quality, low hydrogen content, hydrogenated amorphous silicon (a-Si:H) film is deposited by passing a stream of silane gas (SiH.sub.4) over a high temperature, 2000.degree. C., tungsten (W) filament in the proximity of a high temperature, 400.degree. C., substrate within a low pressure, 8 mTorr, deposition chamber. The silane gas is decomposed into atomic hydrogen and silicon, which in turn collides preferably not more than 20-30 times before being deposited on the hot substrate. The hydrogenated amorphous silicon films thus produced have only about one atomic percent hydrogen, yet have device quality electrical, chemical, and structural properties, despite this lowered hydrogen content.

Deposition of device quality low H content, amorphous silicon films

Fabrication of crystalline or molecular nanostructures with dimensions less than or equal to 1000.ANG. on a substrate surface is achieved by the indirect and/or direct action of a highly-localized field-emission current, which causes atoms of molecular gases introduced into a vacuum chamber to deposit or etch at surface atomic sites that are fixed by the emission-tip location. The tip is shaped to maintain control of the emitting region and is typically about 10.ANG. above the structure. The tip position is stepped in a programmed sequence, with each step taken on detecting the current increase induced by an atomic deposition below the tip. Gas sequences or mixtures can also be programmed, and microstructures of typically 10.sup.2 -10.sup.8 atoms are thereby formed with exact control of the positions and types of atomic constituents. The multi-tipped tool consists of a large array of field-emitting nanostructure probe tip extensions on the end of a metal probe. The nanostructures are spaced in a prescribed, repeating pattern with typical spacings on the order of 400.ANG.. The probe voltage, current and position, as well as CVD or etching gas pressures, are sequentially adjusted to fabricate nanostructures on a nearby substrate, which is typically 10-30.ANG. below the termination points of the probe tip extensions.

Microtip-controlled nanostructure fabrication and multi-tipped field

Fabrication of crystalline or molecular nanostructures with dimensions less han or equal to 1000 .ANG. on a substrate surface is achieved by the indirect and/or direct action of a highly-localized field-emission current, which causes atoms of molecular gases introduced into a vacuum chamber to deposit or etch at surface atomic sites that are fixed by the emission-tip location. The tip is shaped to maintain control of the emitting region and is typically about 10 .ANG. above the structure. The tip position is stepped in a programmed sequence, with each step taken on detecting the current increase induced by an atomic deposition below the tip. Gas sequences or mixtures can also be programmed, and microstructures of typically 10.sup.2 -10.sup.8 atoms are thereby formed with exact control of the positions and types of atomic constituents. The multi-tipped tool consists of a large array of field-emitting nanostructure probe tip extensions on the end of a metal probe. The probe is tapered to a long, narrow, flat end with typical dimensions of 1 cm.times.1 .mu.m. The probe tip extensions typically extend approximately 100 .ANG. beyond the probe surface and their ends are shaped to act as independent field-emission tips, each at an exact atomic location. The nanostructures are spaced in a prescribed, repeating pattern with typical spacings on the order of 400 .ANG.. The probe voltage, current and position, as well as CVD or etching gas pressures, are sequentially adjusted to fabricate nanostructures on a nearby substrate, which is typically 10-30 .ANG. below the termination points of the probe tip extensions.

Microtip-controlled nanostructure fabrication and multi-tipped

A tool consists of an array of field-emitting nanostructure probe tip extensions on the end of a metal probe. The probe is tapered to a long, narrow, flat end with typical dimensions of 1 cm.times.1 .mu.m. The probe tip extensions typically extend approximately 100 .ANG. beyond the probe surface and their ends are shaped to act as independent field-emission tips, each at an exact atomic location. These ends are a single crystal plane terminating in a single crystal unit plane cell having a central atom with a lower work function than the atoms surrounding the central atom. The nanostructures are spaced in a prescribed, repeating pattern with typical spacings on the order of 400 .ANG.. The probe voltage, current and position, as well as CVD or etching gas pressures, are sequentially adjusted to fabricate nanostructures on a nearby substrate, which is typically 10-30 .ANG. below the termination points of the probe tip extensions.

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Louisville, CO, United States of America

Alan C Gallagher