A compound semiconductor transistor may include a channel layer. The compound semiconductor transistor may also include a dielectric layer on the channel layer. The compound semiconductor transistor may further include a gate. The gate may include a vertical base portion through the dielectric layer and electrically contacting the channel layer. The gate may also include a head portion on the dielectric layer and electrically coupled to the vertical base portion of the gate.

A method for producing a semiconductor power device includes forming a gate trench from a surface of the semiconductor layer toward an inside thereof. A first insulation film is formed on the inner surface of the gate trench. The method also includes removing a part on a bottom surface of the gate trench in the first insulation film. A second insulation film having a dielectric constant higher than SiO2 is formed in such a way as to cover the bottom surface of the gate trench exposed by removing the first insulation film.

A method for producing a semiconductor power device includes forming a gate trench from a surface of the semiconductor layer toward an inside thereof. A first insulation film is formed on the inner surface of the gate trench. The method also includes removing a part on a bottom surface of the gate trench in the first insulation film. A second insulation film having a dielectric constant higher than SiO2 is formed in such a way as to cover the bottom surface of the gate trench exposed by removing the first insulation film.

A compound semiconductor transistor may include a channel layer. The compound semiconductor transistor may also include a dielectric layer on the channel layer. The compound semiconductor transistor may further include a gate. The gate may include a vertical base portion through the dielectric layer and electrically contacting the channel layer. The gate may also include a head portion on the dielectric layer and electrically coupled to the vertical base portion of the gate.

According to one embodiment, a semiconductor device includes a first semiconductor layer including a nitride semiconductor, a first electrode separated from the first semiconductor layer in a first direction, and a first insulating film including silicon and oxygen and being provided between the first semiconductor layer and the first electrode. The first insulating film has a first thickness in the first direction. The first insulating film includes a first position, and a distance between the first position and the first semiconductor layer is of the first thickness. A first hydrogen concentration of hydrogen at the first position is 2.510.sup.19 atoms/cm.sup.3 or less.

A lateral junction field-effect transistor includes a substrate of a first conductivity type having a dopant concentration; a first semiconductor layer of the first conductivity type having a first dopant concentration lower than the dopant concentration and disposed on the substrate; a second semiconductor layer of a second conductivity type having a second dopant concentration, the second conductivity type being different from the first conductivity type, the second semiconductor layer disposed on the first semiconductor layer; a third semiconductor layer of the first conductivity type having a third dopant concentration, the third semiconductor layer disposed on the second semiconductor layer; a fourth semiconductor layer of the first conductivity type having a fourth dopant concentration lower than the dopant concentration, the fourth semiconductor layer disposed on the third semiconductor layer; a source region and a drain region disposed in the second semiconductor layer and on opposite sides of the third semiconductor layer.

A precursor cell for a transistor having a foundation structure, a mask structure, and a gallium nitride (GaN) PN structure is provided. The mask structure is provided over the foundation structure to expose a first area of a top surface of the foundation structure. The GaN PN structure resides over the first area and at least a portion of the mask structure and has a continuous crystalline structure with no internal regrowth interfaces. The GaN PN structure comprises a drift region over the first area, a control region laterally adjacent the drift region, and a PN junction formed between the drift region and the control region. Since the drift region and the control region form the PN junction having no internal regrowth interfaces, the GaN PN structure has a continuous crystalline structure with reduced regrowth related defects at the interface of the drift region and the control region.

One aspect of the disclosure relates to a method of forming a semiconductor structure. The method may include: forming a set of openings within a substrate; forming an insulator layer within each opening in the set of openings; recessing the substrate between adjacent openings containing the insulator layer in the set of openings to form a set of insulator pillars on the substrate; forming sigma cavities within the recessed substrate between adjacent insulator pillars in the set of insulator pillars; and filling the sigma cavities with a semiconductor material over the recessed substrate between adjacent insulator pillars.

A method of regrowing material includes providing a III-nitride structure including a masking layer and patterning the masking layer to form an etch mask. The method also includes removing, using an in-situ etch, a portion of the III-nitride structure to expose a regrowth region and regrowing a III-nitride material in the regrowth region.

FinFET devices including III-V fin structures and silicon-based source/drain regions are formed on a semiconductor substrate. Silicon is diffused into the III-V fin structures to form n-type junctions. Leakage through the substrate is addressed by forming p-n junctions adjoining the source/drain regions and isolating the III-V fin structures under the channel regions.