Abstract: The present invention discloses a new testing method of group III-nitride wafers. By utilizing the ammonothermal method, GaN or other Group III-nitride wafers can be obtained by slicing the bulk GaN ingots. Since these wafers originate from the same ingot, these wafers have similar properties/qualities. Therefore, properties of wafers sliced from an ingot can be estimated from measurement data obtained from selected number of wafers sliced from the same ingot or an ingot before slicing. These estimated properties can be used for product certificate of untested wafers. This scheme can reduce a significant amount of time, labor and cost related to quality control.

Abstract: The present invention discloses a high-pressure vessel of large size formed with a limited size of e.g. Ni—Cr based precipitation hardenable superalloy. The vessel may have multiple zones. For instance, the high-pressure vessel may be divided into at least three regions with flow-restricting devices and the crystallization region is set higher temperature than other regions. This structure helps to reliably seal both ends of the high-pressure vessel, and at the same time, may help to greatly reduce unfavorable precipitation of group III nitride at the bottom of the vessel. This invention also discloses novel procedures to grow crystals with improved purity, transparency and structural quality. Alkali metal-containing mineralizers are charged with minimum exposure to oxygen and moisture until the high-pressure vessel is filled with ammonia. Several methods to reduce oxygen contamination during the process steps are presented.

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 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 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 enables obtaining high temperature difference between the dissolution region and the crystallization region without decreasing conductance through the device.

Abstract: The present invention discloses a high-pressure vessel of large size formed with a limited size of e.g. Ni—Cr based precipitation hardenable superalloy. The vessel may have multiple zones. For instance, the high-pressure vessel may be divided into at least three regions with flow-restricting devices and the crystallization region is set higher temperature than other regions. This structure helps to reliably seal both ends of the high-pressure vessel, and at the same time, may help to greatly reduce unfavorable precipitation of group III nitride at the bottom of the vessel. This invention also discloses novel procedures to grow crystals with improved purity, transparency and structural quality. Alkali metal-containing mineralizers are charged with minimum exposure to oxygen and moisture until the high-pressure vessel is filled with ammonia. Several methods to reduce oxygen contamination during the process steps are presented.

Abstract: The present invention discloses a new testing method of group III-nitride wafers. By utilizing the ammonothermal method, GaN or other Group III-nitride wafers can be obtained by slicing the bulk GaN ingots. Since these wafers originate from the same ingot, these wafers have similar properties/qualities. Therefore, properties of wafers sliced from an ingot can be estimated from measurement data obtained from selected number of wafers sliced from the same ingot or an ingot before slicing. These estimated properties can be used for product certificate of untested wafers. This scheme can reduce a significant amount of time, labor and cost related to quality control.

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: The present invention discloses a production method for group III nitride ingots or pieces such as wafers. To solve the coloration problem in the wafers grown by the ammonothermal method, the present invention composed of the following steps; growth of group III nitride ingots by the ammonothermal method, slicing of the ingots into wafers, annealing of the wafers in a manner that avoids dissociation or decomposition of the wafers. This annealing process is effective to improve transparency of the wafers and/or otherwise remove contaminants from wafers.