A method for improving breakdown voltage of a Laterally Diffused Metal Oxide Semiconductor (LDMOS) includes biasing a first well of a Field Effect Transistor (FET) to a first voltage. The first well is laterally separated from a second well. An isolation ring is charged to a second voltage in response to the first voltage exceeding a breakdown voltage of a diode connected between the isolation ring and the first well. The isolation ring laterally surrounds the FET and contacts a buried layer (BL) extending below the first well and the second well. A substrate is biased to a third voltage being less than or equal to the first voltage. The substrate laterally extends below the BL and contacts the BL.

A semiconductor integrated circuit includes: a p.sup.-type semiconductor substrate defining a high-potential side circuit area and a low-potential side circuit area separated from each other; a high-side n well provided in an upper part of the semiconductor substrate in the high-potential side circuit area; a high-side p well provided in the high-side n well; and a p-type semiconductor region provided in an upper part of the semiconductor substrate in the low-potential side circuit area; and n.sup.+-type semiconductor region provided to be brought contact with the p-type semiconductor region, wherein a whole n-type semiconductor region including the n.sup.+-type semiconductor region, has an impurity concentration higher than an impurity concentration of the high-side n well.

A semiconductor device includes: a first-conductivity-type drift layer including a first-conductivity-type impurity, vacancy-oxygen-hydrogen complex defects each caused by a vacancy, an oxygen atom, and a hydrogen atom, divacancy-and-vacancy-phosphorus complex defects, having a trap density level lower than a trap density level of the vacancy-oxygen-hydrogen complex defect, and third complex defects; a plurality of donor layers provided at different depths in a depth direction of the first-conductivity-type drift layer, wherein each of the plurality of donor layers includes donors caused by the vacancy-oxygen-hydrogen complex defects, and each of the plurality of donor layers has an impurity concentration distribution that includes a first portion with a maximum impurity concentration and a second portion with a concentration gradient in which the impurity concentration is reduced from the first portion to both main surfaces of the first-conductivity-type drift layer; and a second-conductivity-type semiconductor region provided on one main surface of the first-conductivity-type drift layer.

A device includes a laterally diffused MOSFET, which in turn includes n-type source and drain regions in a p-type semiconductor substrate. A gate electrode is located over the semiconductor substrate between the source region and the drain region. An isolation region is laterally spaced apart from the source region, and is bounded by an n-type buried layer and an n-type well region that reaches from a surface of the substrate to the buried layer. A p-type doped region and an n-type doped region are disposed within the isolation region, the p-type doped region and the n-type doped region forming a diode. A first conductive path connects the n-type doped region to the source region, and a second conductive path connects the p-type doped region to the gate electrode.

To provide a semiconductor apparatus including: a semiconductor substrate having a drift region; an emitter region provided inside the semiconductor substrate and above the drift region; a base region provided between the emitter and drift regions; an accumulation region provided between the base and drift regions; and a plurality of gate trench portions provided to penetrate the accumulation region from an upper surface of the semiconductor substrate. The base region has: a low concentration base region provided in contact with the gate trench portions; and a high concentration base region provided apart from the gate trench portions and having a doping concentration higher than the low concentration base region. The high concentration base region is provided below the emitter region, and a width of the high concentration base region in a depth direction of the semiconductor substrate is larger than 0.1 m.

A lateral junction diode device includes a substrate having at least a semiconductor surface layer. A depletion-mode LDMOS device is in the semiconductor surface layer including a source, drain, and a gate above a gate dielectric, and a channel region under the gate on the gate dielectric. A drift region is between the channel region and the drain, wherein the drain also provides a cathode for the lateral junction diode device. An embedded diode includes a second cathode and an anode that is shared with the device. The embedded diode is junction isolated by an isolation region located between the anode and the source. The anode and isolation region are directly connected to the gate and the second cathode is directly connected to the source.

The semiconductor device includes a chip which has a main surface, a first conductivity type channel region which is formed in a surface layer portion of the main surface, a second conductivity type drift region which is formed in the surface layer portion of the main surface so as to be adjacent to the channel region, a gate insulating film which covers the channel region and the drift region on the main surface, and a polysilicon gate which has a second conductivity type first portion which faces the channel region across the gate insulating film and a first conductivity type second portion which faces the drift region across the gate insulating film and forms a pn-junction portion with the first portion.

In a semiconductor device using, as a FWD, a diode formed in a silicon carbide (SiC) substrate, while preventing gate oscillation, an increase of switching loss is suppressed at the time of a temperature increase also. A semiconductor device includes: a transistor element; a diode element formed in a SiC substrate; and a resistive element that is electrically connected to a gate of the transistor element, and has a resistor temperature coefficient which is within the range of 15010.sup.6/K. The resistive element has a resistor formed of a ceramic-containing material.

A lateral double-diffused metal-oxide-semiconductor (LDMOS) transistor including a breakdown voltage clamp includes a drain n+ region, a source n+ region, a gate, and a p-type reduced surface field (PRSF) layer including one or more bridge portions. Each of the one or more bridge portions extends below the drain n+ region in a thickness direction. Another LDMOS transistor includes a drain n+ region, a source n+ region, a gate, an n-type reduced surface field (NRSF) layer disposed between the source n+ region and the drain n+ region in a lateral direction, a PRSF layer disposed below the NRSF layer in a thickness direction orthogonal to the lateral direction, and a p-type buried layer (PBL) disposed below the PRSF layer in the thickness direction. The drain n+ region is disposed over the PBL in the thickness direction.

A semiconductor device according to an embodiment is provided with a plurality of active barrier sections each of which is enclosed by a plurality of element isolation sections each of which is configured of a closed pattern. Namely, the plurality of active barrier sections are electrically isolated from each other.