According to one embodiment, a semiconductor device includes first and second nitride regions, and first and second electrodes. Thea first nitride region includes a first region and a second region. The first region includes Al.sub.x1Ga.sub.1x1N (0<x11). The second region includes Al.sub.x2Ga.sub.1x2N (0x2<x1). The second nitride region includes Al.sub.y2Ga.sub.1y2N (0<y21). The second region is between the first region and the second nitride region. A composition ratio x1 decreases along a first direction from the first region to the second nitride region. A composition ratio x2 decreases along the first direction. A first change rate of the composition ratio x1 with respect to a change in a position along the first direction is higher than a second change rate of the composition ratio x2 with respect to the change in the position along the first direction.

According to one embodiment, a semiconductor device includes first and second nitride regions, and first and second electrodes. Thea first nitride region includes a first region and a second region. The first region includes Al.sub.x1Ga.sub.1x1N (0<x11). The second region includes Al.sub.x2Ga.sub.1x2N (0x2<x1). The second nitride region includes Al.sub.y2Ga.sub.1y2N (0<y21). The second region is between the first region and the second nitride region. A composition ratio x1 decreases along a first direction from the first region to the second nitride region. A composition ratio x2 decreases along the first direction. A first change rate of the composition ratio x1 with respect to a change in a position along the first direction is higher than a second change rate of the composition ratio x2 with respect to the change in the position along the first direction.

Systems and methods for fabricating diamond films are described. One method includes chemically hardening a glass substrate. A nanocrystalline diamond layer may be deposited on the glass substrate via a CV D-based deposition process on at least a first side of the substrate. An ultrananocrystalline diamond layer may be deposited on at least the first side of the substrate.

Systems and methods for fabricating diamond films are described. One method includes chemically hardening a glass substrate. A nanocrystalline diamond layer may be deposited on the glass substrate via a CV D-based deposition process on at least a first side of the substrate. An ultrananocrystalline diamond layer may be deposited on at least the first side of the substrate.

A semiconductor device includes a semiconductor layer of a first conductivity type having a first main surface at one side and a second main surface at another side, a trench gate structure including a gate trench formed in the first main surface of the semiconductor layer, and a gate electrode embedded in the gate trench via a gate insulating layer, a trench source structure including a source trench formed deeper than the gate trench and across an interval from the gate trench in the first main surface of the semiconductor layer, a source electrode embedded in the source trench, and a deep well region of a second conductivity type formed in a region of the semiconductor layer along the source trench, a ratio of a depth of the trench source structure with respect to a depth of the trench gate structure being not less than 1.5 and not more than 4.0, a body region of the second conductivity type formed in a region of a surface layer portion of the first main surface of the semiconductor layer between the gate trench and the source trench, a source region of the first conductivity type formed in a surface layer portion of the body region, and a drain electrode connected to the second main surface of the semiconductor layer.

A semiconductor structure and a manufacturing method of the semiconductor structure are provided. The semiconductor structure includes an n-type semiconductor layer, a functional layer, a p-type semiconductor layer, a first AlN layer and a first heavily doped n-type semiconductor layer arranged in sequence. The first AlN layer is provided to reduce the diffusion of p-type ions from the p-type semiconductor layer into the first heavily doped n-type semiconductor layer, to avoid a thicker tunneling junction caused by n-type ions/p-type ions co-doping, to improve the tunneling effect of carriers, to enhance the uniformity of the current density distribution of the first heavily doped n-type semiconductor layer injected into the p-type semiconductor layer, to solve the problem that the p-type semiconductor layer has low carrier mobility and high resistivity.

A semiconductor structure and a manufacturing method of the semiconductor structure are provided. The semiconductor structure includes an n-type semiconductor layer, a functional layer, a p-type semiconductor layer, a first AlN layer and a first heavily doped n-type semiconductor layer arranged in sequence. The first AlN layer is provided to reduce the diffusion of p-type ions from the p-type semiconductor layer into the first heavily doped n-type semiconductor layer, to avoid a thicker tunneling junction caused by n-type ions/p-type ions co-doping, to improve the tunneling effect of carriers, to enhance the uniformity of the current density distribution of the first heavily doped n-type semiconductor layer injected into the p-type semiconductor layer, to solve the problem that the p-type semiconductor layer has low carrier mobility and high resistivity.

Provided is a semiconductor device having transistor and diode sections. The semiconductor device comprises: a gate metal layer provided above the upper surface of a semiconductor substrate; an emitter electrode provided above the upper surface of the semiconductor substrate; a first conductivity-type emitter region provided on the semiconductor substrate upper surface side in the transistor section; a gate trench section, which is provided on the semiconductor substrate upper surface side in the transistor section, is electrically connected to the gate metal layer, and is in contact with the emitter region; an emitter trench section, which is provided on the semiconductor substrate upper surface side in the diode section, and is electrically connected to the emitter electrode; and a dummy trench section, which is provided on the semiconductor substrate upper surface side, is electrically connected to the gate metal layer, and is not in contact with the emitter region.

A diode device includes a first well in a semiconductor substrate, a second well in the semiconductor substrate surrounding the first well, and a low-doped region between the first well and the second well in the semiconductor substrate. The first well and the second well have opposite conductivity types, creating a PIN diode. The diode device also includes a field plate structure over the low-doped region between the wells. The field plate structure includes a single crystal semiconductor over a first dielectric layer and/or a polyconductor gate over a second dielectric layer. The field plate structure provides high voltage isolation resulting in increased breakdown voltage for the PIN diode at reduced costs compared to conventional processes. In certain embodiments, the diode device may have a breakdown voltage of greater than 35 Volts.

Various embodiments of the present disclosure are directed towards a method for forming a semiconductor structure, the method includes forming a buffer layer over a substrate. An active layer is formed on the buffer layer. A top electrode is formed on the active layer. An etch process is performed on the buffer layer and the substrate to define a plurality of pillar structures. The plurality of pillar structures include a first pillar structure laterally offset from a second pillar structure. At least portions of the first and second pillar structures are spaced laterally between sidewalls of the top electrode.