A method of performing HVPE heteroepitaxy comprises exposing a substrate to a carrier gas, a first precursor gas, a Group II/III element, and ternary-forming gasses (V/VI group precursor), to form a heteroepitaxial growth of a binary, ternary, and/or quaternary compound on the substrate; wherein the carrier gas is H.sub.2, wherein the first precursor gas is HCl, the Group II/III element comprises at least one of Zn, Cd, Hg, Al, Ga, and In; and wherein the ternary-forming gasses comprise at least two or more of AsH.sub.3 (arsine), PH.sub.3 (phosphine), H.sub.2Se (hydrogen selenide), H.sub.2Te (hydrogen telluride), SbH.sub.3 (hydrogen antimonide, or antimony tri-hydride, or stibine), H.sub.2S (hydrogen sulfide), NH.sub.3 (ammonia), and HF (hydrogen fluoride); flowing the carrier gas over the Group II/III element; exposing the substrate to the ternary-forming gasses in a predetermined ratio of first ternary-forming gas to second ternary-forming gas (1tf:2tf ratio); and changing the 1tf:2tf ratio over time.

A method for fabricating an (Al,Ga,In,B)N or III-nitride semiconductor device, including performing a growth of III-nitride or (Al,Ga,In,B)N material including a p-n junction with an active region and using metal-organic chemical vapor deposition (MOCVD) or chemical vapor deposition; and performing a subsequent regrowth of n-type (Al,Ga,In,B)N or III-nitride material using MOCVD or chemical vapor deposition while utilizing a pulsed delta n-type doping scheme to realize an abrupt, smoother surface of the n-type material and a higher carrier concentration in the n-type material. In another example, the method comprises forming a mesa having a top surface; and activating magnesium in the p-type GaN of the (Al,Ga,In,B)N material through openings in the top surface that expose the p-type GaN's surface. The openings are formed before or after the subsequent regrowth of the tunnel junction.

The present application provides a process for preparing an epitaxy wafer, and an epitaxy wafer prepared therefrom. The process comprises: step S1: providing a semiconductor substrate wafer, conducting an epitaxy process and forming an epitaxy layer on the wafer; and step S2: conducting a thermal treatment to the wafer to eliminate the haze pattern of the epitaxy layer. According to the process, the thermal treatment after the epitaxy process can facilitate the orientation of atoms on the wafer surface toward the lowest energy orientation, so that the atoms of the epitaxy layer arrange and accumulate uniformly. Therefore, the haze pattern on the wafer surface can be eliminated.

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 10.sup.4 cm.sup.−2 and an inclusion density below 10.sup.4 cm.sup.−3 and/or a MV density below 10.sup.4 cm.sup.−3.

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 10.sup.4 cm.sup.−2 and an inclusion density below 10.sup.4 cm.sup.−3 and/or a MV density below 10.sup.4 cm.sup.−3.

In the present invention, a chemical-vapor-deposition silicon carbide (SIC) bulk having an improved etching characteristic includes silicon carbide (SIC) manufactured by a chemical vapor deposition method using MTS (methyltrichlorosilane), hydrogen (H.sub.2), and nitrogen (N.sub.2) gases. The SIC manufactured by the chemical vapor deposition method is β-SiC (3C-SiC), and 6H-SiC is present in the SIC manufactured by the chemical vapor deposition method. Five peaks having a reference code of 03-065-0360 and a peak having a reference code of 00-049-1428 are confirmed to be present from XRD analysis of the silicon carbide bulk, and a nitrogen concentration value is 4.0×10.sup.18 atoms/cm.sup.3 or more at a depth of 1,500 nm or more from the surface of the bulk, which is a metastable layer.

In the present invention, a chemical-vapor-deposition silicon carbide (SIC) bulk having an improved etching characteristic includes silicon carbide (SIC) manufactured by a chemical vapor deposition method using MTS (methyltrichlorosilane), hydrogen (H.sub.2), and nitrogen (N.sub.2) gases. The SIC manufactured by the chemical vapor deposition method is β-SiC (3C-SiC), and 6H-SiC is present in the SIC manufactured by the chemical vapor deposition method. Five peaks having a reference code of 03-065-0360 and a peak having a reference code of 00-049-1428 are confirmed to be present from XRD analysis of the silicon carbide bulk, and a nitrogen concentration value is 4.0×10.sup.18 atoms/cm.sup.3 or more at a depth of 1,500 nm or more from the surface of the bulk, which is a metastable layer.

A method of forming a silicon germanium layer on a surface of a substrate and a system for forming a silicon germanium layer are disclosed. Examples of the disclosure provide a method that includes providing a plurality of growth precursors to control and/or promote parasitic gas-phase and surface reactions, such that greater control of the film (e.g., thickness and/or composition) uniformity can be realized.

The present invention is aimed at providing: a GaN substrate wafer having an improved productivity, which can be preferably used for the production of a nitride semiconductor device in which a device structure is arranged on a GaN substrate having a carrier concentration increased by doping; and a method of producing the same. Provided is a (0001)-oriented GaN wafer which includes a first region arranged on an N-polar side and a second region arranged on a Ga-polar side via a regrowth interface therebetween. In this GaN wafer, the second region has a minimum thickness of 20 μm to 300 μm, and contains a region having a higher donor impurity total concentration than the first region. In the second region, a region within a specific length from a main surface of the Ga-polar side of the GaN substrate wafer is defined as a main doped region, and the second region may be doped such that at least the main doped region has a donor impurity total concentration of 1×10.sup.18 atoms/cm.sup.3 or higher.

A window assembly heat transfer system is disclosed in which a window member has a selected transparency to monitored or sensed light wavelengths. One or more passages are provided in the window member for flowing a single-phase or two-phase heat transfer fluid, the passages being optically non-transparent to the monitored or sensed light wavelengths. A mechanism allows either evaporation or condensation of the fluid and/or balancing of a flow of the fluid within the passages. In one embodiment, the window assembly can be made by producing passages in a top surface of a first single plate, optionally producing passages in a bottom surface of a second single plate and bonding the top surface of the first plate to a bottom surface of a second single plate to form the window member with the passage or passages. In another embodiment, the window assembly can be made by providing a core around which the window member material is grown and thereafter removing the core to produce the passage or passages.