A buffer layer on a silicon carbide substrate and a method of forming the same are disclosed. The buffer layer includes at least two layers of silicon carbide films, in which at least each lower one is doped at a top surface thereof with predetermined ions. As a result, at the top surface of the silicon carbide film, a barrier with different parameter is formed, which can block dislocation defects that have spread into the silicon carbide film from further upward propagation in the silicon carbide film.

The present disclosure provides a radio frequency device, a silicon carbide homoepitaxial substrate and a manufacturing method thereof. The manufacturing method of the silicon carbide homoepitaxial substrate includes: providing an N-type silicon carbide substrate, forming first grooves in the N-type silicon carbide substrate; forming a defect repair layer on inner walls of the first grooves and outside the first grooves, and forming second grooves in the defect repair layer corresponding to the first grooves; forming an unintentionally doped silicon carbide layer on the defect repair layer, where the second grooves are fully filled with the unintentionally doped silicon carbide layer.

A rare earth-containing SiC substrate includes a rare earth element and Al. A concentration of the rare earth element is from 1×10.sup.16 atoms/cm.sup.3 to 1×10.sup.19 atoms/cm.sup.3 inclusive and a concentration of Al is from 1×10.sup.16 atoms/cm.sup.3 to 1×10.sup.21 atoms/cm.sup.3 inclusive.

First and second p-type semiconductor regions (electric-field relaxation layers) are formed by ion implantation using a dummy gate and side wall films on both sides of the dummy gate as a mask. In this manner, it is possible to reduce a distance between the first p-type semiconductor region and a trench and a distance between the second p-type semiconductor region and the trench, and symmetry of the first and second p-type semiconductor regions with respect to the trench can be enhanced. As a result, semiconductor elements can be miniaturized, and on-resistance and an electric-field relaxation effect, which are in a trade-off relationship, can be balanced, so that characteristics of the semiconductor elements can be improved.

A method of manufacturing a semiconductor device includes forming a first AlN layer on a first main surface of a single-crystal substrate, partly etching the first AlN layer to form a plurality of pieces of AlN seed crystals on the first main surface from the first AlN layer, and forming a second AlN layer on the first main surface using the AlN seed crystals as growth nuclei.

According to one embodiment, a wafer includes a substrate and a crystal layer. The substrate includes a plurality of SiC regions including SiC and an inter-SiC region including Si provided between the SiC regions. The crystal layer includes a first layer, and a first intermediate layer provided between the substrate and the first layer in a first direction. The first layer includes SiC and nitrogen. The first intermediate layer includes SiC and nitrogen. A second concentration of nitrogen in the first intermediate layer is higher than a first concentration of nitrogen in the first layer.

A method for manufacturing a composite structure comprising a thin layer made of monocrystalline silicon carbide arranged on a carrier substrate made of silicon carbide, the method comprising: a) a step of providing a donor substrate made of monocrystalline SiC, the donor substrate comprising a donor layer produced by epitaxial growth on an initial substrate, the donor layer exhibiting a density of crystal defects that is lower than that of the initial substrate; b) a step of ion implantation of light species into the donor layer, in order to form a buried brittle plane delimiting the thin layer between the buried brittle plane and a free face of the donor layer; c) a succession of n steps of formation of carrier layers, with n greater than or equal to 2, the n carrier layers being arranged on the donor layer successively on one another and forming the carrier substrate, each step of formation comprising a chemical vapor deposition, at a temperature of between 400° C. and 1100° C., in order to form a carrier layer made of polycrystalline SiC, the n chemical vapor depositions being carried out at n different temperatures; d) a step of separation along the buried brittle plane, in order to form, on the one hand, a composite structure comprising the thin layer on the carrier substrate and, on the other hand, the remainder of the donor substrate; and e) a step of mechanical and/or chemical treatment(s) of the composite structure.

Disclosed are a semiconductor device and a manufacturing method therefor. The semiconductor device includes a semiconductor substrate, an epitaxial layer grown on a side of the semiconductor substrate; a quantum dot transport layer disposed on the epitaxial layer; and a gate oxide layer disposed on the quantum dot transport layer. With this arrangement, the semiconductor device provided by the present disclosure may reduce a threshold voltage while ensuring gate electrode reliability.

A semiconductor device and a method of manufacturing a semiconductor device according to one or more embodiments are disclosed. An interface layer is formed by implanting ionized impurities into a first layer comprising single-crystalline silicon carbide (SiC). Surfaces of the interface layer and a second layer comprising polycrystalline silicon carbide (SiC) are activated. The activated surfaces of the interface layer and the second layer are contacted and bonded. A covering layer is formed to cover a top surface and sides of the first layer, sides of the interface layer, and sides of the second layer.

A semiconductor device has a first substrate and a first semiconductor layer having a first semiconductor material formed over the first substrate. A surface of the first semiconductor layer has a first element of the first semiconductor material. A first surface of a second semiconductor layer having the first semiconductor material is joined to the surface of the first semiconductor layer. The first surface of the second semiconductor layer has a second element of the first semiconductor material different from the first element. The first semiconductor material is silicon carbide or cubic silicon carbide. The first element is silicon or carbon, and the second element is carbon or silicon. The semiconductor device provides characteristics of radiation hardening. A third semiconductor layer is formed over a second surface of the second semiconductor layer opposite the first surface. An electrical component is formed over the second semiconductor layer.