The present disclosure describes methods and epitaxial oxide devices with impact ionization. A method can comprise: applying a bias across a semiconductor structure using a first electrical contact and a second electrical contact; injecting a hot electron, from the first electrical contact, through a second semiconductor layer, and into a conduction band of a first epitaxial oxide material; and forming an excess electron-hole pair in an impact ionization region of the first semiconductor layer via impact ionization. The semiconductor structure can comprise: the first electrical contact; the first semiconductor layer with the first epitaxial oxide material with a first bandgap coupled to the first electrical contact; a second semiconductor layer with a second epitaxial oxide material with a second bandgap coupled to the first semiconductor layer; and a second electrical contact coupled to the second semiconductor layer, wherein the second bandgap is wider than the first bandgap.

The present disclosure provides techniques for epitaxial oxide materials, structures and devices. In some embodiments, a semiconductor structure includes an epitaxial oxide heterostructure, including: a substrate; a first epitaxial oxide layer comprising (Ni.sub.x1Mg.sub.y1Zn.sub.1-x1-y1)(Al.sub.q1Ga.sub.1-q1).sub.2O.sub.4 wherein 0≤x1≤1, 0≤y1≤1 and 0≤q1≤1; and a second epitaxial oxide layer comprising (Ni.sub.x2Mg.sub.y2Zn.sub.1-x2-y2)(Al.sub.q2Ga.sub.1-q2).sub.2O.sub.4 wherein 0≤x2≤1, 0≤y2≤1 and 0≤q2≤1. In some cases, at least one condition selected from x1≠x2, y1≠y2, and q1≠q2 is satisfied.

The present disclosure describes epitaxial oxide devices with impact ionization. In some embodiments, a semiconductor device comprises: a first semiconductor layer; a second semiconductor layer coupled to the first semiconductor layer; and a first and a second electrical contact coupled to the second and first semiconductor layers, respectively. The first semiconductor layer can comprise a first epitaxial oxide material with a first bandgap and an impact ionization region. The second semiconductor layer can comprise a second epitaxial oxide material with a second bandgap that is wider than the first bandgap.

The present disclosure provides techniques for epitaxial oxide materials, structures and devices. In some embodiments, a semiconductor structure includes an epitaxial oxide heterostructure, comprising: a substrate; a first epitaxial oxide layer comprising Li(Al.sub.x1Ga.sub.1−x1)O.sub.2 wherein 0≤x1≤1; and a second epitaxial oxide layer comprising (Al.sub.x2Ga.sub.1−x2).sub.2O.sub.3 wherein 0≤x2≤1.

A semiconductor device of an embodiment includes an oxide semiconductor layer. The oxide semiconductor layer includes a metal oxide containing at least one first metal element selected from the group consisting of indium and tin and at least one second metal element selected from the group consisting of zinc, gallium, aluminum, tungsten, and silicon. The oxide semiconductor layer includes a first region in which at least one anion element selected from the group consisting of fluorine and chlorine is contained within a range of 1 atomic % or more and less than 8 atomic % in the metal oxide.

The present disclosure describes epitaxial oxide integrated circuits. In some embodiments, an integrated circuit comprises: a field effect transistor (FET), comprising: a substrate comprising a first oxide material; an epitaxial buried ground plane on the substrate and comprising a second oxide material; an epitaxial buried oxide layer on the epitaxial buried ground plane and comprising a third oxide material; an epitaxial semiconductor layer on the epitaxial buried oxide layer and comprising a fourth oxide material with a first bandgap; a gate layer on the epitaxial semiconductor layer and comprising a fifth oxide material with a second bandgap; electrical contacts; and a waveguide coupled to the field effect transistor. The waveguide can comprise: the epitaxial buried ground plane; the epitaxial buried oxide layer; and a signal conductor, wherein the epitaxial buried oxide layer is between the signal conductor and the epitaxial buried ground plane.

The present disclosure provides techniques for epitaxial oxide materials, structures and devices. In some embodiments, a semiconductor structure includes an epitaxial oxide heterostructure, comprising: a substrate; a first epitaxial oxide layer comprising (Ni.sub.x1Mg.sub.y1Zn.sub.1−x1−yl).sub.2GeO.sub.4 wherein 0≤x1≤1 and 0≤y1≤1; and a second epitaxial oxide layer comprising (Ni.sub.x2Mg.sub.y2Zn.sub.1−x2−y2).sub.2GeO.sub.4 wherein 0≤x2≤1 and 0≤y2≤1. In some cases, either: x1≠x2 and y1=y2; x1=x2 and y1≠y2; or x1≠x2 and y1≠y2. In some embodiments, a semiconductor structure includes an epitaxial oxide heterostructure, comprising: a substrate; a first epitaxial oxide layer comprising (Mg.sub.x1Zn.sub.1−x1)(Al.sub.y1Ga.sub.1−y1).sub.2O.sub.4 wherein 0≤x1≤1 and 0≤y1≤1; and a second epitaxial oxide layer comprising (Ni.sub.x2Mg.sub.y2Zn.sub.1−x2−y2).sub.2GeO.sub.4 wherein 0≤x2≤1 and 0≤y2≤1.

Disclosed is a method of manufacturing a gallium oxide thin film for a power semiconductor using a dopant activation technology that maximizes dopant activation effect and rearrangement effect of lattice in a grown epitaxial at the same time by performing in-situ annealing in a growth condition of a nitrogen atmosphere at the same time as the growth of a doped layer is finished.

The present invention relates to a method for manufacturing a diamond substrate, and more particularly, to a method of growing diamond after forming a structure of an air gap having a crystal correlation with a lower substrate by heat treatment of a photoresist pattern and an air gap forming film material on a substrate such as sapphire (Al.sub.2O.sub.3). Through such a method, a process is simplified and the cost is lowered when large-area/large-diameter single crystal diamond is heterogeneously grown, stress due to differences in a lattice constant and a coefficient of thermal expansion between the heterogeneous substrate and diamond is relieved, and an occurrence of defects or cracks is reduced even when a temperature drops, such that a high-quality single crystal diamond substrate may be manufactured and the diamond substrate may be easily self-separated from the heterogeneous substrate.

Disclosed herein are compositions and methods for making polycrystalline thin films having very large grains sizes and exhibiting improved properties over existing thin films.