摘要:
According to one aspect of the invention, an improved process for preparing a surface of substrate is provided wherein the surface of the substrate is prepared for a chemical mechanical polishing (CMP) process, the CMP process is performed on the surface of the substrate, and the surface of the substrate is finished to clear the substrate surface of any active ingredients from the CMP process. Also, an improved substrate produced by the method is provided. According to one aspect of the invention, particular polishing materials and procedures may be used that allow for increased quality of AlN substrate surfaces.
摘要:
Fabrication of doped and undoped stoichiometric polycrystalline AlN ceramics with high purity is accomplished by, for example, reacting Al pellets with nitrogen gas. Such polycrystalline AlN ceramics may be utilized in the fabrication of high purity AlN single crystals, which may be annealed to enhance a conductivity thereof.
摘要:
Reducing the microvoid (MV) density in AlN ameliorates numerous problems related to cracking during crystal growth, etch pit generation during the polishing, reduction of the optical transparency in an AlN wafer, and, possibly, growth pit formation during epitaxial growth of AlN and/or AlGaN. This facilitates practical crystal production strategies and the formation of large, bulk AlN crystals with low defect densities—e.g., a dislocation density below 104 cm−2 and an inclusion density below 104 cm−3 and/or a MV density below 104 cm−3.
摘要翻译:降低AlN中的微孔(MV)密度改善了与晶体生长期间的开裂有关的许多问题,抛光期间的蚀刻坑产生,AlN晶片中的光学透明度的降低以及可能的AlN的外延生长期间的生长凹坑形成和/ 或AlGaN。 这有助于实际的晶体生产策略和形成具有低缺陷密度的大的大块AlN晶体 - 例如位错密度低于10 -4 cm -2,并且包含密度低于 而且,或者低于10 -4 cm -3的MV密度。
摘要:
Bulk single crystals of AlN having a diameter greater than about 25 mm and dislocation densities of about 10,000 cm−2 or less and high-quality AlN substrates having surfaces of any desired crystallographic orientation fabricated from these bulk crystals.
摘要:
A crucible for growing III-nitride (e.g., aluminum nitride) single crystals is provided. The crucible includes an elongated wall structure defining an interior crystal growth cavity. Embodiments include a plurality of grains and a wall thickness of at least about 1.5 times the average grain size. In particular embodiments, the crucible includes first and second layers of grains the first layer including grains forming an inside surface thereof and the second layer being superposed with the first layer. The crucible may be fabricated from tungsten-rhenium (W—Re) alloys; rhenium (Re); tantalum monocarbide (TaC); tantalum nitride (Ta2N); hafnium nitride (HfN); a mixture of tungsten and tantalum (W—Ta); tungsten (W); and combinations thereof.
摘要:
Silicon and metal are coevaporated onto a silicon substrate in a molecular beam epitaxy system with a larger than stoichiometric amount of silicon so as to epitaxially grow particles of metal silicide embedded in a matrix of single crystal epitaxially grown silicon. The particles interact with incident photons by resonant optical absorption at the surface plasmon resonance frequency. Controlling the substrate temperature and deposition rate and time allows the aspect ratio of the particles to be tailored to desired wavelength photons and polarizations. The plasmon energy may decay as excited charge carriers or phonons, either of which can be monitored to indicate the amount of incident radiation at the selected frequency and polarization.
摘要:
Bulk single crystal of aluminum nitride (AlN) having an areal planar defect density≦100 cm−2. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.
摘要:
Fabrication of doped AlN crystals and/or AlGaN epitaxial layers with high conductivity and mobility is accomplished by, for example, forming mixed crystals including a plurality of impurity species and electrically activating at least a portion of the crystal.
摘要:
Silicon and metal are coevaporated onto a silicon substrate in a molecular beam epitaxy system with a larger than stoichiometric amount of silicon so as to epitaxially grow particles of metal silicide embedded in a matrix of single crystal epitaxially grown silicon. The particles interact with incident photons by resonant optical absorption at the surface plasmon resonance frequency. Controlling the substrate temperature and deposition rate and time allows the aspect ratio of the particles to be tailored to desired wavelength photons and polarizations. The plasmon energy may decay as excited charge carriers or phonons, either of which can be monitored to indicate the amount of incident radiation at the selected frequency and polarization.
摘要:
Bulk single crystals of AlN having a diameter greater than about 25 mm and dislocation densities of about 10,000 cm−2 or less and high-quality AlN substrates having surfaces of any desired crystallographic orientation fabricated from these bulk crystals.