A semiconductor device includes: a gate electrode including a junction portion forming a Schottky junction with a barrier layer; a projecting portion including first and second gate field plates and projecting from the junction portion; and an insulating layer including first and second sidewalls. An angle formed between a highest position of a bottom surface of the first gate field plate and a main surface of a substrate, viewed from the first position, is a second elevation angle. An angle formed between an end on the drain electrode side of a lowest portion of a bottom surface of the second gate field plate and the main surface, viewed from the first position, is a third elevation angle. The second elevation angle is larger than the third elevation angle. The bottom surface of the second gate field plate includes an inclined surface where a distance from the barrier layer monotonically increases.

A buried wordline structure fabrication method includes: providing a first trench in a semiconductor substrate, wherein the first trench has a tip on its bottom; performing epitaxial growth within the first trench to reduce the depth of the tip on the bottom of the first trench; and forming a gate dielectric layer on an inner wall of the first trench and filling a gate conductive layer within the first trench to form the buried wordline structure.

A trench transistor. The transistor including: a semiconductor region, a trench structure formed in the semiconductor region; a gate insulation layer and an electrically conductive gate layer formed on the gate insulation layer in the trench structure, and a gate contact, which is electrically conductively connected to the gate layer in an edge area of the trench transistor. A thickness of the gate insulation layer in the edge area of the trench transistor is greater than in an active area of the trench transistor.

A semiconductor device and a method of manufacturing a semiconductor device are provided. The semiconductor device includes a semiconductor substrate and a word line structure. The semiconductor substrate has an active region. The word line structure is disposed in the active region of the semiconductor substrate. The word line structure includes a first work function layer, a second work function layer, and a buffer structure. The second work function layer is on the first work function layer. The buffer structure is between the first work function layer and the second work function layer.

A thin film transistor includes a stack of an active layer, a gate dielectric, and a gate electrode in a forward or in a reverse order. The active layer includes a compound semiconductor material containing oxygen, at least one acceptor-type element selected from Ga and W, and at least one heavy post-transition metal element selected from In and Sn. An atomic percentage of the at least one heavy post-transition metal element at a first surface portion of the active layer that contacts the gate dielectric is higher than an atomic percentage of the at least one heavy post-transition metal element at a second surface portion of the active layer located on an opposite side of the gate dielectric. The front channel current may be increased, and the back channel leakage current may be decreased.

An HEMT with a stair-like compound layer as a drain includes a first III-V compound layer. A second III-V compound layer is disposed on the first III-V compound layer. The composition of the first III-V compound layer and the second III-V compound layer are different from each other. A source electrode, a gate electrode and a drain electrode are disposed on the second III-V compound layer. The gate electrode is disposed between the source electrode and the drain electrode. A first P-type III-V compound layer is disposed between the drain electrode and the second III-V compound layer. The first P-type III-V compound layer is stair-like.

The present disclosure relates to a vertical bipolar junction transistor. A vertical bipolar junction transistor includes a high concentration doping region emitter terminal disposed on a semiconductor substrate; a high concentration doping region collector terminal disposed on a semiconductor substrate; a high concentration doping region base terminal disposed between the emitter terminal and the collector terminal; a drift region having a first doping concentration surrounding the emitter terminal and being deeper than either the base terminal or the collector terminal; a base layer disposed below the drift region; a collector layer in contact with the base layer, the collector layer having a second doping concentration higher than the first doping concentration. The manufacturing cost of the vertical bipolar junction transistor can be lowered and a current gain can be elevated using a low-cost BCD process.

A semiconductor device production method includes a first step of forming a planar silicon layer on a silicon substrate and forming first and second pillar-shaped silicon layers on the planar silicon layer; a second step of forming a gate insulating film around the first and second pillar-shaped silicon layers, forming a metal film and a polysilicon film around the gate insulating film, controlling a thickness of the polysilicon film to be smaller than a half of a distance between the first and second pillar-shaped silicon layers, depositing a resist, exposing the polysilicon film on side walls of upper portions of the first and second pillar-shaped semiconductor layers, etching-away the exposed polysilicon film, stripping the third resist, and etching-away the metal film; and a third step of forming a resist for forming a gate line and performing anisotropic etching to form a gate line and first and second gate electrodes.

A semiconductor device includes a semiconductor substrate including, on a first surface, first trenches and a second trench linked to each of the first trenches. The semiconductor substrate includes: a p-type end layer extending from the first surface to a position closer to a second surface of the semiconductor substrate than an end of each of the first trenches on a second surface side and including a longitudinal end of each of the first trenches in a plan view of the first surface; a first p-type layer provided in a region between adjacent first trenches, and contacting the first electrode provided on the first surface; an n-type barrier layer; a second p-type layer. The second trench separates the p-type end layer from the first p-type layer and the second p-type layer.

An integrated circuit includes an NMOS transistor, a PMOS transistor and a vertical bipolar transistor. The vertical bipolar transistor has an intrinsic base with a band barrier at least 25 meV high at a surface boundary of the intrinsic base, except at an emitter-base junction with an emitter, and except at a base-collector junction with a collector. The intrinsic base may be laterally surrounded by an extrinsic base with a higher dopant density than the intrinsic base, wherein a higher dopant density provides the band barrier at lateral surfaces of the intrinsic base. A gate may be disposed on a gate dielectric layer over a top surface boundary of the intrinsic base adjacent to the emitter. The gate is configured to accumulate the intrinsic base immediately under the gate dielectric layer, providing the band barrier at the top surface boundary of the intrinsic base.