The present invention provides a semiconductor device, comprising: a substrate (10); a stack of III-nitride transition layers (11) disposed on the substrate (10), the stack of III-nitride transition layers (11) maintaining an epitaxial relationship to the substrate (10); a first III-nitride layer (121) disposed on the stack of III-nitride transition layers (11); and a second III-nitride layer (122) disposed on the first III-nitride layer (121), the second III-nitride layer (122) having a band gap energy greater than that of the first III-nitride layer (121), wherein the stack of III-nitride transition layers (11) comprises a first transition layer (111), a second transition layer (112) on the first transition layer (111), and a third transition layer (113) on the second transition layer (112), and wherein the second transition layer (112) has a minimum aluminium molar ratio among the first transition layer (111), the second transition layer (112) and third transition layer (113). The present invention also relates to a method of forming such semiconductor device. The semiconductor device according to the present invention advantageously has a dislocation density less than or equal to 1×10.sup.9 cm.sup.−2 in the first III-nitride layer (121).

One or more semiconductor structures comprising a hole draining structure are provided. A semiconductor structure has a first layer formed over a substrate. The first layer has a first concentration of a metal material. The semiconductor structure has a second layer formed over the first layer. The second layer has a second concentration of the metal material different than the first concentration of the metal material. The semiconductor structure has a hole draining structure formed from a superlattice formed between the first layer and the second layer. The hole draining structure has a concentration of the metal material increasing towards the first layer and decreasing towards the second layer.

A semiconductor device may include a first single crystal silicon layer having a first percentage of silicon 28; a second single crystal silicon layer having a second percentage of silicon 28 higher than the first percentage of silicon 28; and a superlattice between the first and second single crystal silicon layers. The superlattice may include stacked groups of layers, with each group of layers including stacked base silicon monolayers defining a base silicon portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base silicon portions.

The present disclosure describes epitaxial oxide field effect transistors (FETs). In some embodiments, a FET comprises: a substrate comprising an oxide material; an epitaxial semiconductor layer on the substrate; a gate layer on the epitaxial semiconductor layer; and electrical contacts. In some cases, the epitaxial semiconductor layer can comprise a superlattice comprising a first and a second set of layers comprising oxide materials with a first and second bandgap. The gate layer can comprise an oxide material with a third bandgap, wherein the third bandgap is wider than the first bandgap. In some cases, the epitaxial semiconductor layer can comprise a second oxide material with a first bandgap, wherein the second oxide material comprises single crystal A.sub.xB.sub.1-xO.sub.n, wherein 0<x<1.0, wherein A is Al and/or Ga, wherein B is Mg, Ni, a rare earth, Er, Gd, Ir, Bi, or Li.

Disclosed are a semiconductor structure and a manufacturing method therefor, solving a problem that a surface of an epitaxial layer is not easy to flatten as the epitaxial layer has a large stress. The semiconductor structure includes: a substrate; a patterned AlN/AlGaN seed layer on the substrate; and an AlGaN epitaxial layer formed on the patterned AlN/AlGaN seed layer.

A superlattice structure includes a substrate. A first superlattice stack is disposed on the substrate. The first superlattice stack includes a first superlattice layer, a second superlattice layer and a third superlattice layer disposed from bottom to top. Three stress relaxation layers respectively disposed between the first superlattice layer and the second superlattice layer, the second superlattice layer and the third superlattice layer and on the third superlattice layer. Each of the stress relaxation layers includes a group III-V compound layer. The thickness of each of the stress relaxation layers should be greater than a relaxation critical thickness.

The present disclosure describes epitaxial oxide high electron mobility transistors (HEMTs). In some embodiments, a HEMT comprises: a substrate; a template layer on the substrate; a first epitaxial semiconductor layer on the template layer; and a second epitaxial semiconductor layer on the first epitaxial semiconductor layer. The template layer can comprise crystalline metallic Al(111). The first epitaxial semiconductor layer can comprise (Al.sub.xGa.sub.1-x).sub.yO.sub.z, wherein 0≤x≤1, 1≤y≤3, and 2≤z≤4, wherein the (Al.sub.xGa.sub.1-x).sub.yO.sub.z comprises a Pna21 space group, and wherein the (Al.sub.xGa.sub.1-x).sub.yO.sub.z comprises a first conductivity type formed via polarization. The second epitaxial semiconductor layer can comprise a second oxide material.

A semiconductor structure includes a superlattice structure, an electrical isolation layer, a channel layer, and a composition gradient layer. The superlattice structure is disposed on a substrate, the electrical isolation layer is disposed on the superlattice structure, the channel layer is disposed on the electrical isolation layer, and the composition gradient layer is disposed between the electrical isolation layer and the superlattice structure. The composition gradient layer and the superlattice structure include a same group III element, and the atomic percentage of the same group III element in the composition gradient layer is gradually decreased in the direction from the superlattice structure to the electrical isolation layer. In addition, a high electron mobility transistor including the semiconductor structure is also provided.

A semiconductor device includes: an active region extending on a substrate in a first direction; a gate structure intersecting the active region and extending on the substrate in a second direction; and a source/drain region on the active region on at least one side of the gate structure. The source/drain region may include a first epitaxial layer on the active region and including impurities of a first conductivity type in a first concentration, a second epitaxial layer on the first epitaxial layer and including the impurities of the first conductivity type in a second concentration, and a first barrier layer between the first epitaxial layer and the second epitaxial layer, wherein the first barrier layer includes doped oxygen.

The present application provides a semiconductor structure. The semiconductor structure includes a channel layer and a barrier layer provided on the channel layer. The barrier layer includes multiple barrier layers arranged in a stack, the multiple barrier sub-layers include at least three barrier sub-layers, and Al component proportions of the multiple barrier sub-layers vary along a growth direction of the barrier layer for at least one up-and-down fluctuation.