A Schottky barrier diode includes a substrate, a first semiconductor layer formed on the substrate, a second semiconductor layer formed on the first semiconductor layer, and a metal layer formed on the second semiconductor layer to form a Schottky barrier, wherein the first semiconductor layer and the second semiconductor layer are formed of different materials, and a conduction band offset between the first semiconductor layer and the second semiconductor layer is less than a set value.

A compound semiconductor device includes: a compound semiconductor area in which a compound semiconductor plug is embedded and formed; and an ohmic electrode provided on the compound semiconductor plug, wherein the compound semiconductor plug includes, in a side surface portion that is as an interface with the compound semiconductor area, a high concentration dopant layer containing a dopant whose concentration is higher than that of other portions.

A process of forming a field effect transistor (FET) of a type of high electron mobility transistor (HEMT) reducing damages caused in a semiconductor layer is disclosed. The process carries out steps of: (a) depositing an insulating film on a semiconductor stack; (b) depositing a conductive film on the insulating film; (c) forming an opening in the conductive film and the insulating film by a dry-etching using ions of reactive gas to expose a surface of the semiconductor stack; and (d) forming a gate electrode to be in contact with the surface of the semiconductor stack through the opening, the gate electrode filling the opening in the conductive film and the insulating film.

A semiconductor device includes an n-type semiconductor layer; a first metal layer provided on the n-type semiconductor layer, the first metal layer including first atoms capable of being n-type impurities in the n-type semiconductor layer; a second metal layer provided on the first metal layer, the second metal layer including titanium atoms; a third metal layer provided on the second metal layer; and a second atom capable of being a p-type impurity in the n-type semiconductor layer. The second atom and a part of the titanium atoms are included in a vicinity of an interface between the first metal layer and the second metal layer.

Systems and methods of reversibly controlling the oxygen vacancy concentration and distribution in oxide heterostructures consisting of electronically conducting In.sub.2O.sub.3 films grown on ionically conducting Y.sub.2O.sub.3-stabilized ZrO.sub.2 substrates. Oxygen ion redistribution across the heterointerface is induced using an applied electric field oriented in the plane of the interface, resulting in controlled oxygen vacancy (and hence electron) doping of the film and possible orders-of-magnitude enhancement of the film's electrical conduction. The reversible modified behavior is dependent on interface properties and is attained without cation doping or changes in the gas environment in contact with the sample.

A semiconductor device includes an n-doped monocrystalline semiconductor substrate having a substrate surface, an amorphous n-doped semiconductor surface layer at the substrate surface of the n-doped monocrystalline semiconductor substrate, and a Schottky-junction forming material in contact with the amorphous n-doped semiconductor surface layer. The Schottky-junction forming material forms at least one Schottky contact with the amorphous n-doped semiconductor surface layer.

A process for producing a component includes a structure made of III-V material(s) on the surface of a substrate, the structure comprising at least one upper contact level defined on the surface of a first III-V material and a lower contact level defined on the surface of a second III-V material, comprising: successive operations of encapsulation of the structure with at least one dielectric; making primary apertures in a dielectric for the two contacts; making secondary apertures in a dielectric for the two contacts; at least partial filling of the apertures with at least one metallic material so as to produce upper contact bottom metallization and at least one upper contact pad in contact with the metallization for each of said contacts. A component produced by the process is also provided. The component may be a laser diode.

A four-terminal GaN transistor and methods of manufacture, the transistor having source and drain regions and preferably two T-shaped gate electrodes, wherein a stem of one of the two T-shaped gate electrodes is more closely located to the source region than it is to a stem of the other one of the two T-shaped gate electrodes and wherein the stem of the other one of the two T-shaped gate electrodes is more closely located to the drain region than it is to the stem of said one of the two T-shaped gate electrodes. The the gate closer to the source region is a T-gate, and the proximity of the two gates is less than 500 nm from each other. The spacing between the stem of the RF gate and source region and the stem of the DC gate and drain region are preferably defined by self-aligned fabrication techniques. The four-terminal GaN transistor is capable of operation in the W-band (75 to 100 GHz).

Example embodiments relate to enhancement-mode high electron mobility transistors. One embodiment includes a method for manufacturing an enhancement-mode high electron mobility transistor. The method includes providing a stack of layers. The stack of layers includes a substrate, a III-V channel layer over the substrate, a III-V barrier layer on the channel layer, a p-doped III-V layer on the III-V barrier layer, and a Schottky contact interlayer on the p-doped III-V layer. The p-doped III-V layer has a first surface area. The Schottky contact interlayer has a second surface area. The second surface area is less than the first surface area. The second surface area leaves a peripheral part of a top surface of the p-doped III-V layer uncovered. The method also includes depositing a metal gate on the Schottky contact interlayer.

An HEMT includes a semiconductor body, which includes a semiconductor heterostructure, and a conductive gate region. The gate region includes: a contact region, which is made of a first metal material and contacts the semiconductor body to form a Schottky junction; a barrier region, which is made of a second metal material and is set on the contact region; and a top region, which extends on the barrier region and is made of a third metal material, which has a resistivity lower than the resistivity of the first metal material. The HEMT moreover comprises a dielectric region, which includes at least one front dielectric subregion, which extends over the contact region, delimiting a front opening that gives out onto the contact region; and wherein the barrier region extends into the front opening and over at least part of the front dielectric subregion.