Integrated circuits with improved laterally diffused metal oxide semiconductor (LDMOS) structures, and methods of fabricating the same, are provided. An exemplary LDMOS integrated circuit includes an n-type reduced surface field, a p-type body well disposed on a lateral side of the n-type reduced surface field region, a shallow trench isolation structure disposed within the n-type reduced surface field region, and a gate structure disposed partially over the p-type body well, partially over the n-type reduced surface field region, partially over the shallow trench isolation structure, and partially within the shallow trench isolation structure.

A transistor includes a trench formed in a semiconductor substrate. A conductive spacer is formed in the trench and offset from a first sidewall of the trench. A dielectric material is formed in the trench and surrounds the conductive spacer. A drift region is formed in the semiconductor substrate adjacent to the first sidewall and a first portion of a second sidewall of the trench. A drain region is formed in the drift region adjacent to a second portion of the second sidewall. A first gate region overlaps a portion of the drift region and is formed separate from the conductive spacer.

A semiconductor device includes a semiconductor substrate, a trench, and a gate structure. The trench is disposed in the semiconductor substrate. The gate structure is disposed on the semiconductor substrate. The gate structure includes a gate electrode, a first gate oxide layer, and a second gate oxide layer. A first portion of the gate electrode is disposed in the trench, and a second portion of the gate electrode is disposed outside the trench. The first gate oxide layer is disposed between the gate electrode and the semiconductor substrate. At least a portion of the first gate oxide layer is disposed in the trench. The second gate oxide layer is disposed between the second portion of the gate electrode and the semiconductor substrate in a vertical direction. A thickness of the second gate oxide layer is greater than a thickness of the first gate oxide layer.

A lateral double-diffused metal-oxide-semiconductor field effect (LDMOS) transistor includes a silicon semiconductor structure, a dielectric layer at least partially disposed in a trench of the silicon semiconductor structure in a thickness direction, and a gate conductor embedded in the dielectric layer and extending into the trench in the thickness direction. The dielectric layer and the gate conductor are at least substantially symmetric with respect to a center axis of the trench extending in the thickness direction, as seen when the LDMOS transistor is viewed cross-sectionally in a direction orthogonal to the lateral and thickness directions.

A semiconductor structure includes an active region, an isolation structure, a first gate structure, and a second gate structure. The active region is disposed over a semiconductor substrate and has a first portion, a second portion, and a third portion. The third portion is between the first portion and the second portion. A shape of the first portion is different from a shape of the third portion, in a top view. The isolation structure is disposed over the semiconductor substrate and surrounds the active region. The first gate structure is disposed between the first portion and the third portion of the active region. The second gate structure is disposed between the second portion and the third portion of the active region.

An object of the present invention is to provide high-performance highly-reliable power semiconductor device.

The semiconductor device according to the present invention is provided with a semiconductor substrate of a first conductive type, a drain electrode formed on a back side of the semiconductor substrate, a drift layer of the first conductive type formed on a semiconductor substrate, a source area of the first conductive type, a current-diffused layer of the first conductive type electrically connected to the drift layer, a body layer of a second conductive type reverse to the first conductive type in contact with the source area and the current-diffused layer, a trench which pierces the source area, the body layer and the current-diffused layer, which is shallower than the body layer, and the bottom of which is in contact with the body layer, a gate insulating film formed on an inner wall of the trench, a gate electrode formed on the gate insulating film, and a gate insulating film protective layer formed between the current-diffused layer and the gate electrode.

In a semiconductor device, a p.sup.+ back gate region (PBG) is arranged in a main surface (S1) between first and second portions (P1, P2) of an n.sup.+ source region (SR), and arranged on a side closer to an n.sup.+ drain region (DR) with respect to the n.sup.+ source region (SR). Thereby, a semiconductor device having a high on-state breakdown voltage can be obtained.

A semiconductor device comprises a transistor formed in a semiconductor substrate having a first main surface. The transistor includes a source region, a drain region, a channel region, a drift zone, and a gate electrode being adjacent to the channel region. The gate electrode is configured to control a conductivity of a channel formed in the channel region, the channel region and the drift zone are disposed along a first direction between the source region and the drain region, the first direction being parallel to the first main surface. The channel region has a shape of a first ridge extending along the first direction, and the transistor includes a first field plate arranged adjacent to the drift zone.

A semiconductor device of the present invention includes a semiconductor layer of a first conductivity type having a cell portion and an outer peripheral portion disposed around the cell portion, formed with a gate trench at a surface side of the cell portion, and a gate electrode buried in the gate trench via a gate insulating film, forming a channel at a portion lateral to the gate trench at ON-time, the outer peripheral portion has a semiconductor surface disposed at a depth position equal to or deeper than a depth of the gate trench, and the semiconductor device further includes a voltage resistant structure having a semiconductor region of a second conductivity type formed in the semiconductor surface of the outer peripheral portion.

In some embodiments, the present disclosure relates to a semiconductor device that includes a well region with a substrate. A source region and a drain region are arranged within the substrate on opposite sides of the well region. A gate electrode is arranged over the well region, has a bottom surface arranged below a topmost surface of the substrate, and extends between the source and drain regions. A trench isolation structure surrounds the source region, the drain region, and the gate electrode. A gate dielectric structure separates the gate electrode from the well region, the source, region, the drain region, and the trench isolation structure. The gate electrode structure has a central portion and a corner portion. The central portion has a first thickness, and the corner portion has a second thickness that is greater than the first thickness.