There is provided a semiconductor device including: a semiconductor layer including a main surface; a plurality of trenches including a plurality of first trench portions and a plurality of second trench portions, respectively; an insulating layer formed in an inner wall of each of the second trench portions; a first electrode buried in each of the second trench portions with the insulating layer interposed between the first electrode and each of the second trench portions; a plurality of insulators buried in the first trench portions so as to cover the first electrode; a contact hole formed at a region between the plurality of first trench portions in the semiconductor layer so as to expose the plurality of insulators; and a second electrode buried in the contact hole.

A MOSFET having a stacked-gate super-junction design and novel termination structure. At least some illustrative embodiments of the device include a conductive (highly-doped with dopants of a first conductivity type) substrate with a lightly-doped epitaxial layer. The volume of the epitaxial layer is substantially filled with a charge compensation structure having vertical trenches forming intermediate mesas. The mesas are moderately doped via the trench sidewalls to have a second conductivity type, while the mesa tops are heavily-doped to have the first conductivity type. Sidewall layers are provided in the vertical trenches, the sidewall layers being a moderately-doped semiconductor of the first conductivity type. The shoulders of the sidewall layers are recessed below the mesa top to receive an overlying gate for controlling a channel between the mesa top and the sidewall layer. The mesa tops are coupled to a source electrode, while a drain electrode is provided on the back side of the substrate.

According to one embodiment, a semiconductor device includes first to fourth semiconductor regions, first and second electrodes, and a first insulating film. The first semiconductor region includes first and second partial regions, and an intermediate partial region. The first electrode is separated from the first partial region. The second electrode includes first and second conductive regions. The second semiconductor region is provided between the first conductive region and the first electrode. The third semiconductor region is provided between the first conductive region and at least a portion of the second semiconductor region. The fourth semiconductor region includes third and fourth partial regions. The fourth partial region is positioned between the first conductive region and the first electrode. The first insulating film is provided, between the fourth partial region and the first electrode, and between the second semiconductor region and the first electrode.

A method for forming a semiconductor device includes: forming a trench structure with trenches in an inner region and an edge region of a SiC semiconductor body such that the trench structure extends from a first surface of the semiconductor body through a second semiconductor layer into a first semiconductor layer and such that the trench structure, in the second semiconductor layer, forms mesa regions; and forming at least one transistor cell at least partially in each of the mesa regions in the inner region. Forming each transistor cell includes forming at least one compensation region. Forming the compensation region includes implanting dopant atoms of a second doping type via sidewalls of the trenches into the mesa regions in the inner region. Forming the compensation region in each mesa region in the inner region includes at least partially covering the edge region with an implantation mask.

Semiconductor device including first semiconductor layer of a first conductivity type, second semiconductor layer of a second conductivity type at a surface of the first semiconductor layer, third semiconductor layer of the first conductivity type selectively provided at a surface of the second layer, and gate electrode embedded in a trench via a gate insulating film. The trench penetrates the second and third layers, and reaches the first layer. A thermal oxide film on the third layer has a thickness less than that of the gate insulating film. Also are an interlayer insulating film on the thermal oxide film, barrier metal on an inner surface of a contact hole selectively opened in the thermal oxide film and the interlayer insulating film, metal plug embedded in the contact hole on the barrier metal, and electrode electrically connected to the second and third layers via the barrier metal and the metal plug.

In a semiconductor device in a wafer state, an element region and a scribe region are defined in one main surface of a semiconductor substrate. In the element region, a vertical MOS transistor is formed as a semiconductor element. In the scribe region, an n-type column region and a p-type column region are defined. An n-type column resistor is formed in the n-type column region. A p-type column resistor is formed in the p-type column region.

Reliability of a semiconductor device is improved by suppressing occurrence of variation in characteristics of the semiconductor device provided with a power MOSFET that has a super junction structure. A fixed charge layer FC is formed in a trench T2 that is formed in an upper surface of a semiconductor substrate SB and is adjacent to a p type body region BD and an n type drift layer DL. The fixed charge layer FC constituting a p column accumulates holes in the semiconductor substrate SB located at a side surface of the trench T2 to form a hole accumulation region HC.

A semiconductor device that achieves both miniaturization and high breakdown voltage is disclosed. The semiconductor device has a gate electrode G1 formed in a trench TR extending in Y direction and a plurality of column regions PC including column regions PC1 to PC3 formed in a drift region ND. The column regions PC1, PC2 and PC3 are provided in a staggered manner to sandwich the trench TR. An angle θ1 formed by a line connecting the centers of the column regions PC1 and PC2 and a line connecting the centers of the column regions PC1 and PC3 is 60 degrees or more and 90 degrees or less.

A Field Effect Transistor (FET) may include a semiconductor substrate having a first conductivity type, a semiconductor layer of the first conductivity type formed over the substrate, and a pair of doped bodies of a second conductivity type opposite the first conductivity type formed in the semiconductor layer. A trench filled with a trench dielectric is formed within a region between the doped bodies. The FET may be a Vertical Metal-Oxide-Semiconductor FET (VMOSFET) including a gate dielectric disposed over the region between the doped bodies and the trench, and a gate electrode disposed over the gate dielectric, wherein the trench operates to prevent breakdown of the gate dielectric, or the FET may be a Junction FET. The FET may be designed to operate at radio frequencies or under heavy-ion bombardment. The semiconductor substrate and the semiconductor layer may comprise a wide band-gap semiconductor such as silicon carbide.

A semiconductor device includes a semiconductor layer structure of a wide band-gap semiconductor material. The semiconductor layer structure includes a drift region having a first conductivity type and a well region having a second conductivity type. A plurality of segmented gate trenches extend in a first direction in the semiconductor layer structure. The segmented gate trenches include respective gate trench segments that are spaced apart from each other in the first direction with intervening regions of the semiconductor layer structure therebetween. Related devices and fabrication methods are also discussed.