A semiconductor substrate includes a first material layer made of a first material and including a plurality of protrusions, and a second material layer made of a second material different from the first material, filling spaces between the plurality of protrusions, and covering the plurality of protrusions. Each of the protrusions includes a tip and a plurality of facets converging at the tip, and adjacent facets of adjacent protrusions are in contact with each other,

A silicon carbide epitaxial substrate according to a present disclosure includes a silicon carbide substrate and a silicon carbide epitaxial layer disposed on the silicon carbide substrate. The silicon carbide epitaxial layer includes a boundary surface in contact with the silicon carbide substrate and a main surface opposite to the boundary surface. The main surface has an outer circumferential edge, an outer circumferential region extending within 5 mm from the outer circumferential edge, and a central region surrounded by the outer circumferential region. When an area density of double Shockley stacking faults in the outer circumferential region is defined as a first area density, and an area density of double Shockley stacking faults in the central region is defined as a second area density, the first area density is five or more times as large as the second area density, the second area density is 0.2 cm.sup.−2 or more.

A nitride semiconductor structure includes a Group III nitride semiconductor portion and a Group II-IV nitride semiconductor portion. The Group III nitride semiconductor portion is single crystalline. The Group III nitride semiconductor portion has a predetermined crystallographic plane. The Group II-IV nitride semiconductor portion is provided on the predetermined crystallographic plane of the Group III nitride semiconductor portion. The Group II-IV nitride semiconductor portion is single crystalline. The Group II-IV nitride semiconductor portion contains a Group II element and a Group IV element. The Group II-IV nitride semiconductor portion forms a heterojunction with the Group III nitride semiconductor portion. The predetermined crystallographic plane is a crystallographic plane other than a (0001) plane.

Method for filling a gap, comprising providing in a deposition chamber a semiconductor substrate having a gap, wherein a bottom of the gap includes a crystalline semiconducting material and wherein a side wall of the gap includes an amorphous material; depositing a silicon precursor in the gap.

There is provided a method for manufacturing a nitride semiconductor template constituted by forming a nitride semiconductor layer on a substrate, comprising: (a) forming a first layer by epitaxially growing a nitride semiconductor containing aluminum on the substrate; (b) applying annealing to the first layer in an inert gas atmosphere; and (c) forming a second layer by epitaxially growing a nitride semiconductor containing aluminum on the first layer by a vapor phase growth after performing (b), and constituting the nitride semiconductor layer by the first layer and the second layer.

A III-nitride-based semiconductor wafer is provided that includes a substrate with a central region and a peripheral edge region. One or more intermediate layers may be optionally provided selected from a buffer layer, a seed layer, or a transition layer. A peripheral edge feature is formed in or on a peripheral edge region of the substrate or the transition layer, with one or more peripheral edge passivation layers or peripheral edge surface texturing. The peripheral edge feature extends only around the peripheral edge and not in the central region. One or more III-nitride-based layers is positioned over the central region. In the central region, the III-nitride layer is an epitaxial layer while in the peripheral edge region, it is a polycrystalline layer. Stress due to lattice mismatches and differences in the coefficient of thermal expansion between the III-nitride layer and the substrate is relieved, minimizing defects.

The disclosure provides a film forming method that enables to obtain an epitaxial film with reduced defects such as dislocations due to a reduced facet growth industrially advantageously, even if the epitaxial film has a corundum structure. When forming an epitaxial film on a crystal-growth surface of a corundum-structured crystal substrate directly or via another layer, using the crystal substrate having an uneven portion on the crystal-growth surface of the crystal substrate, generating and floating atomized droplets by atomizing a raw material solution including a metal; carrying the floated atomized droplets onto a surface of the crystal substrate by using a carrier gas; and causing a thermal reaction of the atomized droplets in a condition of a supply rate limiting state.

A method includes etching a semiconductor substrate to form a trench, with the semiconductor substrate having a sidewall facing the trench, and depositing a first semiconductor layer extending into the trench. The first semiconductor layer includes a first bottom portion at a bottom of the trench, and a first sidewall portion on the sidewall of the semiconductor substrate. The first sidewall portion is removed to reveal the sidewall of the semiconductor substrate. The method further includes depositing a second semiconductor layer extending into the trench, with the second semiconductor layer having a second bottom portion over the first bottom portion, and a second sidewall portion contacting the sidewall of the semiconductor substrate. The second sidewall portion is removed to reveal the sidewall of the semiconductor substrate.

A stacked device is provided. The stacked device includes a plurality of dielectric support bridges on a substrate, and a first two-dimensional (2D) channel layer on each of the plurality of dielectric support bridges. The stacked device further includes a gate dielectric sheet on the first two-dimensional (2D) channel layer, and a second two-dimensional (2D) channel layer on the first two-dimensional (2D) channel layer. The stacked device further includes a second gate dielectric layer on the gate dielectric sheets.

A method of manufacturing nitride semiconductor substrate, comprising: providing silicon-on-insulator substrate which comprises an underlying silicon layer, a buried silicon dioxide layer and a top silicon layer; forming a first nitride semiconductor layer on the top silicon layer; forming, in the first nitride semiconductor layer, a plurality of notches which expose the top silicon layer; removing the top silicon layer and forming a plurality of protrusions and a plurality of recesses on an upper surface of the buried silicon dioxide layer, wherein each of the plurality of protrusions is in contact with the first nitride semiconductor layer, and there is a gap between each of the plurality of recesses and the first nitride semiconductor layer; and epitaxially growing a second nitride semiconductor layer on the first nitride semiconductor layer, such that the first nitride semiconductor layer and the second nitride semiconductor layer form a nitride semiconductor substrate.