Semiconductor device structures and methods for manufacturing the same are provided. The semiconductor device structure includes a substrate, a first nitride semiconductor layer, a second nitride semiconductor layer, a gate electrode, a first electrode, a first via and a second via. The substrate has a first surface and a second surface. The first nitride semiconductor layer is disposed on the first surface of the substrate. The second nitride semiconductor layer is disposed on the first nitride semiconductor layer and has a bandgap exceeding that of the first nitride semiconductor layer. The gate electrode and the first electrode are disposed on the second nitride semiconductor layer. The first via extends from the second surface and is electrically connected to the first electrode. The second via extends from the second surface. The depth of the first via is different from the depth of the second via.

An apparatus is provided which comprises: a first region over a substrate, wherein the first region comprises a first semiconductor material having a L-valley transport energy band structure, a second region in contact with the first region at a junction, wherein the second region comprises a second semiconductor material having a X-valley transport energy band structure, wherein a <111> crystal direction of one or more crystals of the first and second semiconductor materials are substantially orthogonal to the junction, and a metal adjacent to the second region, the metal conductively coupled to the first region through the junction. Other embodiments are also disclosed and claimed.

There is provided a nitride semiconductor laminate, including: a substrate; an electron transit layer provided on the substrate and containing a group III nitride semiconductor; and an electron supply layer provided on the electron transit layer and containing a group III nitride semiconductor, wherein a surface force A of the electron supply layer acting as an attractive force for attracting a probe and a surface of the electron supply layer when measured using the probe consisting of a glass sphere with a diameter of 1 mm covered with Cr, is stronger than a surface force B of Pt when measured under the same condition, and an absolute value |A−B| of a difference between them is 30 μN or more.

A semiconductor device includes a semiconductor substrate, a field-effect transistor arranged at least partially on the semiconductor substrate and used in an analog circuit, and having a P-type gate electrode, an interlayer insulating film arranged on the field-effect transistor, and a hydrogen shielding metal or metallic film arranged on the interlayer insulting film and covering the P-type gate electrode and configured to shield hydrogen.

A nitride semiconductor device is disclosed. The semiconductor device is formed by a process that first deposits a silicon nitride (SiN) film on a semiconductor layer by the lower pressure chemical vapor deposition (LPCVD) technique at a temperature, then, forming an opening in the SiN film for an ohmic electrode. Preparing a photoresist on the SiN film, where the photoresist provides an opening that fully covers the opening in the SiN film, the process exposes a peripheral area around the opening of the SiN film to chlorine (Cl) plasma that may etch the semiconductor layer to form a recess therein. Metals for the ohmic electrode are filled within the recess in the semiconductor layer and the peripheral area of the SiN film. Finally, the metals are alloyed at a temperature lower than the deposition temperature of the SiN film.

A power amplifier comprising a GaN-based high electron mobility transistor (HEMT) device, wherein a power added efficiency (PAE) of the power amplifier is greater than 32% at P1DB during operation of the power amplifier between 26.5 GHz and 30.5 GHz.

A method of manufacturing a semiconductor device including a substrate; a first nitride layer containing gallium on the substrate; and a second nitride layer containing silicon on the first nitride layer includes generating an etchant of a gas containing chlorine atoms or bromine atoms; and selectively removing the second nitride layer, wherein the etchant is generated by plasma discharge of the gas, wherein the second nitride layer and the first nitride layer are prevented from being irradiated with ultraviolet rays generated at a time of the plasma discharge, and wherein the selectively removing the second nitride layer includes etching the second nitride layer under a first atmosphere at a first pressure that is lower than a first saturated vapor pressure of a silicon compound and that is higher than a second saturated vapor pressure of a gallium compound.

An object is to provide a semiconductor device that can prevent organic contamination of an electrode including a plurality of laminated metal layers. A semiconductor device includes: a semiconductor substrate; and an electrode including a plurality of layers laminated on a principal surface of the semiconductor substrate. The electrode includes: a first metal layer in contact with the principal surface of the semiconductor substrate, the first metal layer containing Al; an oxide layer formed on a surface of the first metal layer, the oxide layer containing a metal and oxygen; and a second metal layer formed on a surface of the oxide layer. Concentrations of the oxygen in the oxide layer are higher than or equal to 8.0×10.sup.21/cm.sup.3 and lower than or equal to 4.0×10.sup.22/cm.sup.3.

A bipolar transistor including a first collector layer, a second collector layer, a base layer, and an emitter layer is disposed on a substrate. Etching characteristics of the second collector layer are different from etching characteristics of the first collector layer and the base layer. In plan view, an edge of an interface between the first collector layer and the second collector layer is disposed inside an edge of a lower surface of the base layer, and an edge of an upper surface of the second collector layer coincides with the edge of the lower surface of the base layer or is disposed inside the edge of the lower surface of the base layer.

Embodiments include a transistor and methods of forming a transistor. In an embodiment, the transistor comprises a semiconductor channel, a source electrode on a first side of the semiconductor channel, a drain electrode on a second side of the semiconductor channel, a polarization layer over the semiconductor channel, an insulator stack over the polarization layer, and a gate electrode over the semiconductor channel. In an embodiment, the gate electrode comprises a main body that passes through the insulator stack and the polarization layer, and a first field plate extending out laterally from the main body.