SixPoint Materials, Inc. and Seoul Semiconductor | Date: 2015-01-16
Bulk crystal of group III nitride having thickness greater than 1 mm with improved crystal quality, reduced lattice bowing and/or reduced crack density and methods of making. Bulk crystal has a seed crystal, a first crystalline portion grown on the first side of the seed crystal and a second crystalline portion grown on the second side of the seed crystal. Either or both crystalline portions have an electron concentration and/or an oxygen concentration similar to the seed crystal. The bulk crystal can have an additional seed crystal, with common faces (e.g. same polarity, same crystal plane) of seed crystals joined so that a first crystalline part grows on the first face of the first seed crystal and a second crystalline part grows on the first face of the second seed crystal. Each crystalline parts electron concentration and/or oxygen concentration may be similar to its corresponding seed crystal.
SixPoint Materials, Inc. | Date: 2015-09-24
Present invention discloses a high-pressure vessel of large size formed with a limited size of e.g. NiCr based precipitation hardenable superalloy. 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, at the same time, may help to greatly reduce unfavorable precipitation of group III nitride at the bottom of the vessel. 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. Back etching of seed crystals and a new temperature ramping scheme to improve structural quality are disclosed.
SixPoint Materials, Inc. and Seoul Semiconductor | Date: 2015-09-09
In one instance, the invention provides a substrate for growing a thick layer of group III nitride. The substrate has a first surface prepared for epitaxial growth of group III nitride and a second surface, opposite to the first surface, having a plurality of grooves. The invention also provides a method of producing a thick layer or a bulk crystal of group III nitride using a grooved substrate. The grooved substrate in one configuration grows a thick layer or a bulk crystal of group III nitride with reduced bow and/or spontaneous separation from the substrate.
SixPoint Materials, Inc. and Seoul Semiconductor | Date: 2015-07-22
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.
SixPoint Materials, Inc. and Seoul Semiconductor | Date: 2015-05-24
In one instance, the invention provides a bulk crystal of group III nitride having a thickness of more than 1 mm without cracking above the sides of a seed crystal. This bulk group III nitride crystal is expressed as Ga