A semiconductor device includes a transistor in a semiconductor body having a first main surface. The transistor includes: a source contact electrically connected to a source region; a drain contact electrically connected to a drain region; a gate electrode at the channel region, the channel region and a drift zone disposed along a first direction between the source and drain regions, the first direction being parallel to the first main surface, the channel region patterned into a ridge by adjacent gate trenches formed in the first main surface, the adjacent gate trenches spaced apart in a second direction perpendicular to the first direction, a longitudinal axis of the ridge extending in the first direction and a longitudinal axis of the gate trenches extending in the first direction; and at least one of the source and drain contacts being adjacent to a second main surface opposite the first main surface.

A semiconductor device includes a first conductivity type semiconductor layer, a second conductivity type body region in a semiconductor layer surface portion, a first conductivity type source region in a body region surface, apart from a peripheral edge of the body region, a first conductivity type drain region in the semiconductor layer surface portion apart from the body region, a gate electrode opposing the body region across a gate insulating film between the source and drain regions, an insulating layer on the semiconductor layer, resin on the insulating layer, a source electrode in the insulating layer, electrically connected to the source region, a drain electrode in the insulating layer, electrically connected to the drain region, and conductive shielding in the insulating layer, overlapping in a plan view from a direction normal to a semiconductor layer surface, the drain region and the gate electrode, and covering a region between them.

A lateral trench MOSFET comprises an insulating layer buried in a substrate, a body region in the substrate, an isolation region in the substrate, a first drain/source region over the body region, a second drain/source region in the substrate, wherein the first drain/source region and the second drain/source region are on opposing sides of the isolation region, a drift region comprising a first drift region of a first doping density formed between the second drain/source region and the insulating layer, wherein the first drift region comprises an upper portion surrounded by isolation regions and a lower portion and a second drift region of a second doping density formed between the isolation region and the insulating layer, wherein a height of the second drift region is equal to a height of the lower portion of the first drift region.

Disclosed are methods that employ a mask with openings arranged in a pattern of elongated trenches and holes of varying widths to achieve a linearly graded conductivity level. These methods can be used to form a lateral double-diffused metal oxide semiconductor field effect transistor (LDMOSFET) with a drain drift region having an appropriate type conductivity at a level that increases essentially linearly from the body region to the drain region. Furthermore, these methods also provide for improve manufacturability in that multiple instances of this same pattern can be used during a single dopant implant process to implant a first dopant with a first type (e.g., N-type) conductivity into the drain drift regions of both first and second type LDMOSFETs (e.g., N and P-type LDMOSFETs, respectively). In this case, the drain drift region of a second type LDMOSFET can subsequently be uniformly counter-doped. Also disclosed are the resulting semiconductor structures.

An integrated circuit device includes a pad layer having a body portion with a first doping type laterally adjacent to a drift region portion with a second doping type, a trench formed in the pad layer, the trench extending through an interface of the body portion and the drift region portion, a gate formed in the trench and over a top surface of the pad layer along the interface of the body portion and the drift region portion, an oxide formed in the trench on opposing sides of the gate, and a field plate embedded in the oxide on each of the opposing sides of the gate.

Occurrence of short-channel characteristics and parasitic capacitance of a MOSFET on a SOI substrate is prevented.

A sidewall having a stacked structure obtained by sequentially stacking a silicon oxide film and a nitride film is formed on a side wall of a gate electrode on the SOI substrate. Subsequently, after an epitaxial layer is formed beside the gate electrode, and then, the nitride film is removed. Then, an impurity is implanted into an upper surface of the semiconductor substrate with using the gate electrode and the epitaxial layer as a mask, so that a halo region is formed in only a region of the upper surface of the semiconductor substrate which is right below a vicinity of both ends of the gate electrode.

Occurrence of short-channel characteristics and parasitic capacitance of a MOSFET on a SOI substrate is prevented. A sidewall having a stacked structure obtained by sequentially stacking a silicon oxide film and a nitride film is formed on a side wall of a gate electrode on the SOI substrate. Subsequently, after an epitaxial layer is formed beside the gate electrode, and then, the nitride film is removed. Then, an impurity is implanted into an upper surface of the semiconductor substrate with using the gate electrode and the epitaxial layer as a mask, so that a halo region is formed in only a region of the upper surface of the semiconductor substrate which is right below a vicinity of both ends of the gate electrode.

According to an embodiment, a semiconductor device is provided. The device includes a second region having a greater curvature than a first region. The device includes an epitaxy layer of a first conductivity type, a well of a second conductivity type in the epitaxy layer, a drain in the epitaxy layer, a source in the well, and a bulk in the well and in contact with the source, the bulk having a greater area in the second region than in the first region.

A quasi-lateral diffusion transistor is formed in a semiconductor-on-insulator (SOI) wafer by forming a gate region, a body region, a drift region, and a source region and bonding a handle wafer to the SOI wafer at a first side (e.g., top side) of the SOI wafer; and removing a semiconductor substrate of the SOI wafer, forming a hole in a buried insulator layer of the SOI wafer, and forming a drain region for the transistor at a second side (e.g., bottom side) of the SOI wafer. The body region and the drift region physically contact the buried insulator layer. The drain region is formed in a bottom portion of the drift region exposed by the hole and is laterally offset from the source region. In operation of the quasi-lateral diffusion transistor, a current flow direction through the semiconductor layer is diagonal between the source region and the drain region.

A lateral trench MOSFET comprises an insulating layer buried in a substrate, a body region in the substrate, an isolation region in the substrate, a first drain/source region over the body region, a second drain/source region in the substrate, wherein the first drain/source region and the second drain/source region are on opposing sides of the isolation region, a drift region comprising a first drift region of a first doping density formed between the second drain/source region and the insulating layer, wherein the first drift region comprises an upper portion surrounded by isolation regions and a lower portion and a second drift region of a second doping density formed between the isolation region and the insulating layer, wherein a height of the second drift region is equal to a height of the lower portion of the first drift region.