A production method for a semiconductor device includes: forming a dielectric oxide film on a nitride semiconductor layer, where the dielectric oxide film has a higher relative permittivity than a relative permittivity of silicon dioxide; nitriding the dielectric oxide film to form a dielectric oxynitride film; forming a first silicon nitride film on the dielectric oxynitride film by a thermal film formation method; forming a second silicon nitride film on the first silicon nitride film; forming an opening in the second silicon nitride film and the first silicon nitride film, where the opening reaches the dielectric oxynitride film; and forming a gate electrode on the second silicon nitride film, where the gate electrode is in contact with the dielectric oxynitride film through the opening.

A semiconductor device having a field-effect transistor, including a trench in a semiconductor substrate, a first insulating film in the trench, an intrinsic polycrystalline silicon film over the first insulating film, and first conductivity type impurities in the intrinsic polycrystalline silicon film to form a first conductive film. The first conductive film is etched to form a first gate electrode in the trench. A second insulating film is also formed in the trench above the first insulating film and the first gate electrode, and a first conductivity type doped polycrystalline silicon film, having higher impurity concentration than the first gate electrode is formed over the second insulating film. The doped polycrystalline silicon film is provided in an upper part of the trench to form a second gate electrode.

A nitride semiconductor device includes an electron transit layer (103) that is formed of a nitride semiconductor, an electron supply layer (104) that is formed on the electron transit layer (103), that is formed of a nitride semiconductor whose composition is different from the electron transit layer (103) and that has a recess (109) which reaches the electron transit layer (103) from a surface, a thermal oxide film (111) that is formed on the surface of the electron transit layer (103) exposed within the recess (109), a gate insulating film (110) that is embedded within the recess (109) so as to be in contact with the thermal oxide film (111), a gate electrode (108) that is formed on the gate insulating film (110) and that is opposite to the electron transit layer (103) across the thermal oxide film (111) and the gate insulating film (110), and a source electrode (106) and a drain electrode (107) that are provided on the electron supply layer (104) at an interval such that the gate electrode (108) intervenes therebetween.

A method of manufacturing a semiconductor device includes forming electrode trenches in a semiconductor substrate between semiconductor mesas that separate the electrode trenches, the semiconductor mesas including portions of a drift layer of a first conductivity type and a body layer of a second, complementary conductivity type between a first surface of the semiconductor substrate and the drift layer, respectively. The method further includes forming isolated source zones of the first conductivity type in the semiconductor mesas, the source zones extending from the first surface into the body layer. The method also includes forming separation structures in the semiconductor mesas between neighboring source zones arranged along an extension direction of the semiconductor mesas, the separation structures forming partial or complete constrictions of the semiconductor mesa, respectively.

A power integrated circuit includes a double-diffused metal-oxide-semiconductor (LDMOS) transistor formed in a first portion of the semiconductor layer with a channel being formed in a first body region. The power integrated circuit includes a first deep diffusion region formed in the first deep well under the first body region and in electrical contact with the first body region and a second deep diffusion region formed in the first deep well under the drain drift region and in electrical contact with the first body region. The first deep diffusion region and the second deep diffusion region together form a reduced surface field (RESURF) structure in the LDMOS transistor.

An asymmetric high-k dielectric for reduced gate induced drain leakage in high-k MOSFETs and methods of manufacture are disclosed. The method includes performing an implant process on a high-k dielectric sidewall of a gate structure. The method further includes performing an oxygen annealing process to grow an oxide region on a drain side of the gate structure, while inhibiting oxide growth on a source side of the gate structure adjacent to a source region.

A manufacturing method of a trench power MOSFET is provided. In the manufacturing method, the trench gate structure of the trench power MOSFET is formed in the epitaxial layer and includes an upper doped region, a lower doped region and a middle region interposed therebetween. The upper doped region has a conductive type reverse to that of the lower doped region, and the middle region is an intrinsic or lightly-doped region to form a PIN, P.sup.+/N.sup. or N.sup.+/P.sup. junction. As such, when the trench power MOSFET is in operation, a junction capacitance formed at the PIN, P.sup.+/N.sup. or N.sup.+/P.sup. junction is in series with the parasitic capacitance. Accordingly, the gate-to-drain effective capacitance may be reduced.

The present invention provides a field effect transistor and the method for preparing such a filed effect transistor. The filed effect transistor comprises a semiconductor, germanium nanowires, a first III-V compound layer surrounding the germanium nanowires, a semiconductor barrier layer, a gate dielectric layer and a gate electrode sequentially formed surrounding the first III-V compound layer, and source/drain electrodes are respectively located at each side of the gate electrode and on the first III-V compound layer. According to the present invention, the band width of the barrier layer is greater than that of the first III-V compound layer, and the band curvatures of the barrier layer and the first III-V compound layer are different, therefore, a two-dimensional electron gas (2DEG) is formed in the first III-V compound layer near the barrier layer boundary. Since the 2DEG has higher mobility, the performance of the filed effect transistor improved. Besides, the performance of the filed effect transistor also improved due to the structure is a gate-all-around structure.

Roughly described, a field effect transistor has a first piezoelectric layer supporting a channel, a second piezoelectric layer over the first piezoelectric layer, a dielectric layer having a plurality of dielectric segments separated by a plurality of gaps, the dielectric layer over the second piezoelectric layer, and a gate having a main body and a plurality of tines. The main body of the gate covers at least one dielectric segment of the plurality of dielectric segments and at least two gaps of the plurality of gaps. The plurality of tines have proximal ends connected to the main body of the gate, middle portions projecting through the plurality of gaps, and distal ends separated from the first piezoelectric layer by at least the second piezoelectric layer. The dielectric layer exerts stress, creating a piezoelectric charge in the first piezoelectric layer, changing the threshold voltage of the transistor.

In one implementation, a reduced gate charge field-effect transistor (FET) includes a drift region situated over a drain, a body situated over the drift region, and source diffusions formed in the body. The source diffusions are adjacent a gate trench extending through the body into the drift region and having a dielectric liner and a gate electrode situated therein. The dielectric liner includes an upper segment and a lower segment, the upper segment extending to at least a depth of the source diffusions and being significantly thicker than the lower segment.