Abstract: The present invention in one preferred embodiment discloses a new design of HVPE reactor, which can grow gallium nitride for more than one day without interruption. To avoid clogging in the exhaust system, a second reactor chamber is added after a main reactor where GaN is produced. The second reactor chamber may be configured to enhance ammonium chloride formation, and the powder may be collected efficiently in it. To avoid ammonium chloride formation in the main reactor, the connection between the main reactor and the second reaction chamber can be maintained at elevated temperature. In addition, the second reactor chamber may have two or more exhaust lines. If one exhaust line becomes clogged with powder, the valve for an alternative exhaust line may open and the valve for the clogged line may be closed to avoid overpressuring the system. The quartz-made main reactor may have e.g. a pyrolytic boron nitride liner to collect polycrystalline gallium nitride efficiently.

Abstract: The present invention discloses a new construction of ultracapacitor utilizing particles of transition metal nitride having negligible amount of halide impurities. The construction is expected to attain high specific energy density by using transition metal nitride particles and higher reliability by avoiding potential corrosion of metal components with halide impurities. The transition metal nitride particles are preferably synthesized by basic ammonothermal process, which utilizes supercritical ammonia with alkali metal mineralizers. Transition metal nitride such as vanadium nitride, molybdenum nitride, titanium nitride, nickel nitride, neodymium nitride, iron nitride, etc. can be synthesized in supercritical ammonia with reducing mineralizers such as potassium, sodium, lithium, magnesium, calcium, and aluminum. Since supercritical ammonia has characteristics of both gas and liquid, it can over complicated fine structure or fine particles.

Abstract: The present invention discloses an electronic device using a group III nitride substrate fabricated via the ammonothermal method. By utilizing the high-electron concentration of ammonothermally grown substrates having the dislocation density less than 105 cm?2, combined with a high-purity active layer of Ga1-x-yAlxInyN (0?x?1, 0?y?1) grown by a vapor phase method, the device can attain high level of breakdown voltage as well as low on-resistance. To realize a good matching between the ammonothermally grown substrate and the high-purity active layer, a transition layer is optionally introduced. The active layer is thicker than a depletion region created by a device structure in the active layer.

Abstract: The present invention discloses an electronic device using a group III nitride substrate fabricated via the ammonothermal method. By utilizing the high-electron concentration of ammonothermally grown substrates having the dislocation density less than 105 cm?2, combined with a high-purity active layer of Ga1-x-yAlxInyN (0?x?1, 0?y?1) grown by a vapor phase method, the device can attain high level of breakdown voltage as well as low on-resistance. To realize a good matching between the ammonothermally grown substrate and the high-purity active layer, a transition layer is optionally introduced. The active layer is thicker than a depletion region created by a device structure in the active layer.

Abstract: The present invention discloses an electronic device using a group III nitride substrate fabricated via the ammonothermal method. By utilizing the high-electron concentration of ammonothermally grown substrates having the dislocation density less than 105 cm?2, combined with a high-purity active layer of Ga1-x-yAlxInyN (0?x?1, 0?y?1) grown by a vapor phase method, the device can attain high level of breakdown voltage as well as low on-resistance. To realize a good matching between the ammonothermally grown substrate and the high-purity active layer, a transition layer is optionally introduced. The active layer is thicker than a depletion region created by a device structure in the active layer.

Abstract: The present invention discloses a group III nitride wafer such as GaN, AlN, InN and their alloys having one surface visually distinguishable from the other surface. After slicing of the wafer from a bulk crystal of group III nitride with a mechanical method such as multiple wire saw, the wafer is chemically etched so that one surface of the wafer is visually distinguishable from the other surface. The present invention also discloses a method of producing such wafers.

Abstract: The present invention discloses a method of synthesizing transition metal nitride by using supercritical ammonia. Transition metal nitride such as vanadium nitride, molybdenum nitride, titanium nitride, nickel nitride, neodymium nitride, iron nitride, etc. can be synthesized in supercritical ammonia with reducing mineralizers such as potassium, sodium, lithium, magnesium, calcium, and aluminum. Since supercritical ammonia has characteristics of both gas and liquid, it can over complicated fine structure or fine particles. The new method is suitable for forming a protective coating on complicated structure or forming micro- to nano-sized particles.

Abstract: The present disclosure proves for new design of reactors used for ammonothermal growth of III nitride crystals. The reactors include a region intermediate a source dissolution region and a crystal growth region configured to provide growth of high quality crystals at rates greater than 100 ?m/day. In one embodiment, multiple baffle plates having openings whose location is designed so that there is no direct path through the intermediate region, or with multiple baffle plates having differently sized openings on each plate so that the flow is slowed down and/or exhibit greater mixing are described. The disclosed designs enable obtaining high temperature difference between the dissolution region and the crystallization region without decreasing conductance through the device.

Abstract: The present invention provides a printer which can facilitate temperature control of a machine-plate cylinder section, can allow simple setup, and can facilitate maintenance of printing quality in continuous printing. In the printer, a machine plate is mounted on the outer circumference of a machine-plate cylinder section 12 fixedly provided on a machine-plate drive shaft 1. A fluid whose temperature is regulated is circulated in the machine-plate cylinder section 12.

Abstract: The present invention discloses methods to produce large quantities of polycrystalline GaN for use in the ammonothermal growth of group III-nitride material. High production rates of GaN can be produced in a hydride vapor phase growth system. One drawback to enhanced polycrystalline growth is the increased incorporation of impurities, such as oxygen. A new reactor design using non-oxide material that reduces impurity concentrations is disclosed. Purification of remaining source material after an ammonothermal growth is also disclosed. The methods described produce sufficient quantities of polycrystalline GaN source material for the ammonothermal growth of group III-nitride material.

Abstract: The present invention discloses methods to create higher quality group III-nitride wafers that then generate improvements in the crystalline properties of ingots produced by ammonothermal growth from an initial defective seed. By obtaining future seeds from carefully chosen regions of an ingot produced on a bowed seed crystal, future ingot crystalline properties can be improved. Specifically, the future seeds are optimized if chosen from an area of relieved stress on a cracked ingot or from a carefully chosen N-polar compressed area. When the seeds are sliced out, miscut of 3-10° helps to improve structural quality of successive growth. Additionally a method is proposed to improve crystal quality by using the ammonothermal method to produce a series of ingots, each using a specifically oriented seed from the previous ingot. When employed, these methods enhance the quality of Group III nitride wafers and thus improve the efficiency of any subsequent device.

Abstract: A method of growing high-quality, group-III nitride, bulk single crystals. The group III-nitride bulk crystal is grown in an autoclave in supercritical ammonia using a source material or nutrient that is a group III-nitride polycrystals or group-III metal having a grain size of at least 10 microns or more and a seed crystal that is a group-III nitride single crystal. The group III-nitride polycrystals may be recycled from previous ammonothermal process after annealing in reducing gas at more then 600° C. The autoclave may include an internal chamber that is filled with ammonia, wherein the ammonia is released from the internal chamber into the autoclave when the ammonia attains a supercritical state after the heating of the autoclave, such that convection of the supercritical ammonia transfers source materials and deposits the transferred source materials onto seed crystals, but undissolved particles of the source materials are prevented from being transferred and deposited on the seed crystals.

Abstract: The present invention in one preferred embodiment discloses a new design of HVPE reactor, which can grow gallium nitride for more than one day without interruption. To avoid clogging in the exhaust system, a second reactor chamber is added after a main reactor where GaN is produced. The second reactor chamber may be configured to enhance ammonium chloride formation, and the powder may be collected efficiently in it. To avoid ammonium chloride formation in the main reactor, the connection between the main reactor and the second reaction chamber can be maintained at elevated temperature. In addition, the second reactor chamber may have two or more exhaust lines. If one exhaust line becomes clogged with powder, the valve for an alternative exhaust line may open and the valve for the clogged line may be closed to avoid overpressuring the system. The quartz-made main reactor may have e.g. a pyrolytic boron nitride liner to collect polycrystalline gallium nitride efficiently.

Abstract: The present invention discloses methods to create higher quality group III-nitride wafers that then generate improvements in the crystalline properties of ingots produced by ammonothermal growth from an initial defective seed. By obtaining future seeds from carefully chosen regions of an ingot produced on a bowed seed crystal, future ingot crystalline properties can be improved. Specifically the future seeds are optimized if chosen from an area of relieved stress, on a cracked ingot or from a carefully chosen N-polar compressed area. When the seeds are sliced out, miscut of 3-10° helps to itnprove structural quality of successive growth. Additionally a method is proposed to improve crystal quality by using the ammonothermal method to produce a series of ingots, each using a specifically oriented seed from the previous ingot. When employed, these methods enhance the quality of Group III nitride wafers and thus improve the efficiency of any subsequent device.

Abstract: The present invention discloses methods to create higher quality group III-nitride wafers that then generate improvements in the crystalline properties of ingots produced by ammonothermal growth from an initial defective seed. By obtaining future seeds from carefully chosen regions of an ingot produced on a bowed seed crystal, future ingot crystalline properties can be improved. Specifically, the future seeds are optimized if chosen from an area of relieved stress on a cracked ingot or from a carefully chosen N-polar compressed area. When the seeds are sliced out, miscut of 3-10° helps to improve structural quality of successive growth. Additionally a method is proposed to improve crystal quality by using the ammonothermal method to produce a series of ingots, each using a specifically oriented seed from the previous ingot. When employed, these methods enhance the quality of Group III nitride wafers and thus improve the efficiency of any subsequent device.

Abstract: A method of growing high-quality, group-III nitride, bulk single crystals. The group III-nitride bulk crystal is grown in an autoclave in supercritical ammonia using a source material or nutrient that is a group III-nitride polycrystals or group-III metal having a grain size of at least 10 microns or more and a seed crystal that is a group-III nitride single crystal. The group III-nitride polycrystals may be recycled from previous ammonothermal process after annealing in reducing gas at more then 600° C. The autoclave may include an internal chamber that is filled with ammonia, wherein the ammonia is released from the internal chamber into the autoclave when the ammonia attains a supercritical state after the heating of the autoclave, such that convection of the supercritical ammonia transfers source materials and deposits the transferred source materials onto seed crystals, but undissolved particles of the source materials are prevented from being transferred and deposited on the seed crystals.

Abstract: The invention provides, in one instance, a group III nitride wafer sliced from a group III nitride ingot, polished to remove the surface damage layer and tested with x-ray diffraction. The x-ray incident beam is irradiated at an angle less than 15 degree and diffraction peak intensity is evaluated. The group III nitride wafer passing this test has sufficient surface quality for device fabrication. The invention also provides, in one instance, a method of producing group III nitride wafer by slicing a group III nitride ingot, polishing at least one surface of the wafer, and testing the surface quality with x-ray diffraction having an incident beam angle less than 15 degree to the surface. The invention also provides, in an instance, a test method for testing the surface quality of group III nitride wafers using x-ray diffraction having an incident beam angle less than 15 degree to the surface.

Abstract: The present invention provides a method of growing an ingot of group III nitride. Group III nitride crystals such as GaN are grown by the ammonothermal method on both sides of a seed to form an ingot and the ingot is sliced into wafers. The wafer including the first-generation seed is sliced thicker than the other wafers so that the wafer including the first-generation seed does not break. The wafer including the first-generation seed crystal can be used as a seed for the next ammonothermal growth.

Abstract: The present invention provides a method of growing an ingot of group III nitride. Group III nitride crystals such as GaN are grown by the ammonothermal method on both sides of a seed to form an ingot and the ingot is sliced into wafers. The wafer including the first-generation seed is sliced thicker than the other wafers so that the wafer including the first-generation seed does not break. The wafer including the first-generation seed crystal can be used as a seed for the next ammonothermal growth.

Abstract: The present invention discloses a group III nitride wafer such as GaN, AlN, InN and their alloys having one surface visually distinguishable from the other surface. After slicing of the wafer from a bulk crystal of group III nitride with a mechanical method such as multiple wire saw, the wafer is chemically etched so that one surface of the wafer is visually distinguishable from the other surface. The present invention also discloses a method of producing such wafers.