An 8 inch n-type SiC single crystal substrate of an embodiment has a diameter in the range of 195 to 205 mm, a thickness in the range of 300 ?m to 650 ?m, thicknesses of work-affected layers on both the front and back sides are 0.1 nm or less, and the dopant concentration is 2?10.sup.18/cm.sup.3 or more and 6?10.sup.19/cm.sup.3 or less at least five arbitrarily selected points in the plane within 5% of the thickness of the substrate in the depth direction from the main surface of the substrate.

The present invention provides a method of manufacturing by the sublimation-recrystallization method more accurately detecting a thermal state of a starting material in a crucible and enabling control of the growth conditions while manufacturing an SiC single crystal. The method obtains the high frequency current to be supplied through the induction coil by a converter for converting AC current to DC current and an inverter means for converting the DC current output from the converter to a high frequency to obtain a high frequency current, obtains a grasp, in advance, of a relationship between a variation over time of a DC equivalent resistivity (DCV/DCI), calculated from a DC voltage value (DCV) and DC current value (DCI) converted by the converter at the time of growth of the silicon carbide single crystal, and a density of micropipes formed in the grown silicon carbide single crystal, and adjusts at least one of the DCV or DCI at the converter based on the relationship of the DC equivalent resistivity and micropipe density grasped in advance.

The present invention provides a method of raising the rate of reduction of the dislocation density accompanying growth of an SiC single crystal to counter the increase in the threading screw dislocations formed near the interface of the seed crystal and grown SiC single crystal and thereby produce an SiC single-crystal ingot with a small threading screw dislocation density from the initial stage of growth. The present invention is a method for producing a silicon carbide single-crystal ingot growing a silicon carbide single crystal on a growth face of a seed crystal consisting of a silicon carbide single crystal by a physical vapor transport method so as to produce a silicon carbide single-crystal ingot, the method for producing a silicon carbide single-crystal ingot comprising forming step bunching with heights of steps of 10 ?m to 1 mm and spans of terraces of 200 ?m to 1 mm on the growth face of the seed crystal and making the silicon carbide single crystal grow on the growth face of the seed crystal by the physical vapor transport method.

The present invention is aimed at providing a method of manufacturing a silicon carbide epitaxial wafer by which a plurality of silicon carbide epitaxial layers of a predetermined layer thickness can be precisely formed. In the present invention, a first n-type SiC epitaxial layer is formed on an n-type SiC substrate so that the rate of change in impurity concentration between the n-type SiC substrate and the first n-type SiC epitaxial layer will be greater than or equal to 20%. A second n-type SiC epitaxial layer is formed on the first n-type SiC epitaxial layer so that the rate of change in impurity concentration between the first n-type SiC epitaxial layer and the second n-type SiC epitaxial layer will be greater than or equal to 20%.

A crystal growth method, including providing a seed crystal in a crystal growth furnace, and forming a crystal on the seed crystal along a first direction after multiple time points, is provided. The crystal includes multiple sub-crystals stacked along the first direction, a corresponding one of the sub-crystals is formed at each of the time points, and the sub-crystals include multiple end surfaces away from the seed crystal, so that a difference value of maximum temperatures of any two of the end surfaces is less than or equal to 20 degrees. A wafer is also provided.

A method of conditioning MoCl.sub.5 comprises heating a container of MoCl.sub.5 to a temperature ranging from approximately 140 C. to 190 C. for a period ranging from approximately 2 hours to approximately 100 hours to produce a MoCl.sub.5-containing composition comprising approximately 10% weight to approximately 60% weight of Phase 1 MoCl.sub.5 and 90% weight to approximately 40% weight of Phase 2 MoCl.sub.5 as determined by X-ray diffraction. This MoCl.sub.5-containing composition is expected to be more thermally stable and provides stable vapor supply.

The present invention discloses a molecular beam epitaxy under vector strong magnetic field and an in-situ characterization apparatus thereof. The apparatus mainly consists of an inverted T-shaped ultrahigh vacuum growth and characterization chamber with a compact structure and a strong magnet. The inverted T-shaped vacuum chamber portion, which disposed in the room-temperature chamber of the strong magnet, includes a compact epitaxial growth sample stage, a device capable of rotating angle between the growth and magnetic field directions, and an in-situ characterization apparatus. The portion disposed below the strong magnet includes a molecular beam source component such as evaporation source, plasma source etc., and a vacuum-pumping system. The present invention surmounts effectively the technical problems between the small volume of the strong magnetic field chamber and numerous components of the growth and test system, and realizes the molecular beam epitaxial growth and in-situ characterization under the strong magnetic field.

A PVT method is utilized for production of single crystals in an apparatus, which comprises a growth cell, a process chamber in which the growth cell is located and a heating device surrounding the process chamber for heating the growth cell. In this method, a source material and a seed are introduced into the growth cell, and the process chamber is filled with a process gas and the growth cell is heated, causing the source material to sublimated and resublimated at the seed. An apparatus designed for production of single crystals using the PVT method includes a highly heatable growth cell for accommodation of a source material and a seed, a process chamber accommodating the growth cell with a connection to a process gas source for filling it with a process gas, and a heating device for heating the growth cell.

The present invention provides a method of raising the rate of reduction of the dislocation density accompanying growth of an SiC single crystal to counter the increase in the threading screw dislocations formed near the interface of the seed crystal and grown SiC single crystal and thereby produce an SiC single-crystal ingot with a small threading screw dislocation density from the initial stage of growth. The present invention is a method for producing a silicon carbide single-crystal ingot growing a silicon carbide single crystal on a growth face of a seed crystal consisting of a silicon carbide single crystal by a physical vapor transport method so as to produce a silicon carbide single-crystal ingot, the method for producing a silicon carbide single-crystal ingot comprising forming step bunching with heights of steps of 10 m to 1 mm and spans of terraces of 200 m to 1 mm on the growth face of the seed crystal and making the silicon carbide single crystal grow on the growth face of the seed crystal by the physical vapor transport method.

A method for fabricating a III-nitride semiconductor body that includes high temperature and low temperature growth steps.