Abstract: An electro-optically triggered power switch is disclosed utilizing a wide bandgap, high purity III-nitride semiconductor material such as BN, AlN, GaN, InN and their compounds. The device is electro-optically triggered using a laser diode operating at a wavelength of 10 to 50 nanometers off the material's bandgap, and at a power level of 10 to 100 times less than that required in a conventionally triggered device. The disclosed device may be configured as a high power RF MOSFET, IGBT, FET, or HEMT that can be electro-optically controlled using photons rather than an electrical signal. Electro-optic control lowers the power losses in the semiconductor device, decreases the turn-on time, and simplifies the drive signal requirements. It also allows the power devices to be operated from the millisecond to the sub-picosecond timeframe, thus allowing the power device to be operated at RF frequencies (i.e., kilohertz to terahertz range) and at high temperatures where the bandgap changes with temperature.

Abstract: An electro-optically triggered power switch is disclosed utilizing a wide bandgap, high purity III-nitride semiconductor material such as BN, AlN, GaN, InN and their compounds. The device is electro-optically triggered using a laser diode operating at a wavelength of 10 to 50 nanometers off the material's bandgap, and at a power level of 10 to 100 times less than that required in a conventionally triggered device. The disclosed device may be configured as a high power RF MOSFET, IGBT, FET, or HEMT that can be electro-optically controlled using photons rather than an electrical signal. Electro-optic control lowers the power losses in the semiconductor device, decreases the turn-on time, and simplifies the drive signal requirements. It also allows the power devices to be operated from the millisecond to the sub-picosecond timeframe, thus allowing the power device to be operated at RF frequencies (i.e., kilohertz to terahertz range) and at high temperatures where the bandgap changes with temperature.

Abstract: An electro-optically triggered power switch is disclosed utilizing a wide bandgap, high purity III-nitride semiconductor material such as BN, AN, GaN, InN and their compounds. The device is electro-optically triggered using a laser diode operating at a wavelength of 10 to 50 nanometers off the material's bandgap, and at a power level of 10 to 100 times less than that required in a conventionally triggered device. The disclosed device may be configured as a high power RF MOSFET, IGBT, FET, or HEMT that can be electro-optically controlled using photons rather than an electrical signal. Electro-optic control lowers the power losses in the semiconductor device, decreases the turn-on time, and simplifies the drive signal requirements. It also allows the power devices to be operated from the millisecond to the sub-picosecond timeframe, thus allowing the power device to be operated at RF frequencies (i.e., kilohertz to terahertz range) and at high temperatures where the bandgap changes with temperature.

Abstract: A crucible is provided that is thermally stable at high temperatures and is suitable for use in the growth of large, bulk AlN, AlxGa1-xN or other nitride single crystals. The crucible is comprised of specially treated tantalum. During the initial treatment, the walls of the crucible are carburized, thus achieving a crucible that can be subjected to high temperatures without deformation. Once the carburization of the tantalum is complete, the crucible undergoes further treatment to protect the surfaces that are expected to come into contact with nitride vapors during crystal growth with a layer of TaN. If the crucible is to be used with a graphite furnace, only the inner surfaces of the crucible are converted to TaN, thus keeping TaC surfaces adjacent to the graphite furnace elements. If the crucible is to be used with a non-graphite furnace, both the inner and outer surfaces of the crucible are converted to TaN.

Abstract: A method for fabricating a p-n heterojunction device is provided, the device being preferably comprised of an n-type GaN layer co-doped with silicon and zinc and a p-type AlGaN layer. The device may also include a p-type GaN capping layer. The device can be grown on any of a variety of different base substrates, the base substrate comprised of either a single substrate or a single substrate and an intermediary layer. The device can be grown directly onto the surface of the substrate without the inclusion of a low temperature buffer layer.

Abstract: A low defect (e.g., dislocation and micropipe) density silicon carbide (SiC) is provided as well as an apparatus and method for growing the same. The SiC crystal, grown using sublimation techniques, is preferably divided into two stages of growth. During the first stage of growth, the crystal grows in a normal direction while simultaneously expanding laterally. Although dislocations and other material defects may propagate within the axially grown material, defect propagation and generation in the laterally grown material are substantially reduced, if not altogether eliminated. After the crystal has expanded to the desired diameter, the second stage of growth begins in which lateral growth is suppressed and normal growth is enhanced. A substantially reduced defect density is maintained within the axially grown material that is based on the laterally grown first stage material.

Abstract: A low defect (e.g., dislocation and micropipe) density silicon carbide (SiC) is provided as well as an apparatus and method for growing the same. The SiC crystal, grown using sublimation techniques, is preferably divided into two stages of growth. During the first stage of growth, the crystal grows in a normal direction while simultaneously expanding laterally. Although dislocations and other material defects may propagate within the axially grown material, defect propagation and generation in the laterally grown material are substantially reduced, if not altogether eliminated. After the crystal has expanded to the desired diameter, the second stage of growth begins in which lateral growth is suppressed and normal growth is enhanced. A substantially reduced defect density is maintained within the axially grown material that is based on the laterally grown first stage material.

Abstract: A low defect (e.g., dislocation and micropipe) density silicon carbide (SiC) is provided as well as an apparatus and method for growing the same. The SiC crystal, grown using sublimation techniques, is preferably divided into two stages of growth. During the first stage of growth, the crystal grows in a normal direction while simultaneously expanding laterally. Although dislocations and other material defects may propagate within the axially grown material, defect propagation and generation in the laterally grown material are substantially reduced, if not altogether eliminated. After the crystal has expanded to the desired diameter, the second stage of growth begins in which lateral growth is suppressed and normal growth is enhanced. A substantially reduced defect density is maintained within the axially grown material that is based on the laterally grown first stage material.

Abstract: A method for fabricating a p-n heterojunction device is provided, the device being preferably comprised of an n-type GaN layer co-doped with silicon and zinc and a p-type AlGaN layer. The device may also include a p-type GaN capping layer. The device can be grown on any of a variety of different base substrates, the base substrate comprised of either a single substrate or a single substrate and an intermediary layer. The device can be grown directly onto the surface of the substrate without the inclusion of a low temperature buffer layer.

Abstract: A low defect (e.g., dislocation and micropipe) density silicon carbide (SiC) is provided as well as an apparatus and method for growing the same. The SiC crystal, grown using sublimation techniques, is preferably divided into two stages of growth. During the first stage of growth, the crystal grows in a normal direction while simultaneously expanding laterally. Although dislocations and other material defects may propagate within the axially grown material, defect propagation and generation in the laterally grown material are substantially reduced, if not altogether eliminated. After the crystal has expanded to the desired diameter, the second stage of growth begins in which lateral growth is suppressed and normal growth is enhanced. A substantially reduced defect density is maintained within the axially grown material that is based on the laterally grown first stage material.

Abstract: A low defect (e.g., dislocation and micropipe) density silicon carbide (SiC) is provided as well as an apparatus and method for growing the same. The SiC crystal, growing using sublimation techniques, is preferably divided into two stages of growth. During the first stage of growth, the crystal grows in a normal direction while simultaneously expanding laterally. Although dislocation and other material defects may propagate within the axially grown material, defect propagation and generation in the laterally grown material are substantially reduced, if not altogether eliminated. After the crystal has expanded to the desired diameter, the second stage of growth begins in which lateral growth is suppressed and normal growth is enhanced. A substantially reduced defect density is maintained within the axially grown material that is based on the laterally grown first stage material.

Abstract: A low dislocation density silicon carbide (SiC) is provided as well as an apparatus and method for growing the same. The SiC crystal, grown using sublimation techniques, is preferably divided into two stages of growth. During the first stage of growth, the crystal grows in a normal direction while simultaneously expanding laterally. Although dislocations and other material defects may propagate within the axially grown material, defect propagation and generation in the laterally grown material are substantially reduced, if not altogether eliminated. After the crystal has expanded to the desired diameter, the second stage of growth begins in which lateral growth is suppressed and normal growth is enhanced. A substantially reduced defect density is maintained within the axially grown material that is based on the laterally grown first stage material.

Abstract: A low dislocation density silicon carbide (SiC) is provided as well as an apparatus and method for growing the same. The SiC crystal, grown using sublimation techniques, is preferably divided into two stages of growth. During the first stage of growth, the crystal grows in a normal direction while simultaneously expanding laterally. Although dislocations and other material defects may propagate within the axially grown material, defect propagation and generation in the laterally grown material are substantially reduced, if not altogether eliminated. After the crystal has expanded to the desired diameter, the second stage of growth begins in which lateral growth is suppressed and normal growth is enhanced. A substantially reduced defect density is maintained within the axially grown material that is based on the laterally grown first stage material.

Abstract: A low dislocation density silicon carbide (SiC) is provided as well as an apparatus and method for growing the same. The SiC crystal, grown using sublimation techniques, is preferably divided into two stages of growth. During the first stage of growth, the crystal grows in a normal direction while simultaneously expanding laterally. Although dislocations and other material defects may propagate within the axially grown material, defect propagation and generation in the laterally grown material are substantially reduced, if not altogether eliminated. After the crystal has expanded to the desired diameter, the second stage of growth begins in which lateral growth is suppressed and normal growth is enhanced. A substantially reduced defect density is maintained within the axially grown material that is based on the laterally grown first stage material.

Abstract: An ionizable material is ejected in the shape of a cylindrical column from a cathode-nozzle toward an anode and subjected to a very short, high voltage pulse of electrical current having sufficient magnitude to create a high magnetic field which implodes the cylindrical column of ionizable material to a very high density plasma that emits long wave length x-rays. Accurate and reliably reproduced x-ray bursts are provided through coupling of the cathode and anode to the high voltage pulse generator without substantially degrading the pulse. The conductors between the pulse generator and the cathode and anode are of a configuration whereby a magnetic field is used to prevent the electron losses by tapering the spacing between feed conductors and shaping the feed conductors so that space-charge flow is retrapped and made usable.