A semiconductor device includes: an FET structure that is formed next to a looped trench on a semiconductor substrate and that has an n.sup.+ emitter region and an n.sup. drain region facing each other in the depth direction of the looped trench across a p-type base region; a p-type floating region formed on the side of the looped trench opposite to the FET structure; and an emitter connecting part that is electrically connected to the n.sup.+ emitter region and a trench gate provided in the same trench, the emitter connecting part and the trench gate being insulated from each other by the looped trench. The trench gate faces the FET structure, and the emitter connecting part faces the p-type floating region, across an insulating film.

In one embodiment, a power MOSFET cell includes an N+ silicon substrate having a drain electrode. An N-type drift layer is grown over the substrate. An N-type layer, having a higher dopant concentration than the drift region, is then formed along with a trench having sidewalls. A P-well is formed in the N-type layer, and an N+ source region is formed in the P-well. A gate is formed over the P-well's lateral channel and has a vertical extension into the trench. A positive gate voltage inverts the lateral channel and increases the vertical conduction along the sidewalls to reduce on-resistance. A vertical shield field plate is also located next to the sidewalls and may be connected to the gate. The field plate laterally depletes the N-type layer when the device is off to increase the breakdown voltage. A buried layer and sinker enable the use of a topside drain electrode.

A power semiconductor device includes a semiconductor substrate having a drift region, a gate electrode trench in the semiconductor substrate and a field electrode needle trench in the semiconductor substrate. The gate electrode trench extends into the drift region and includes a gate electrode. The gate electrode is arranged in the gate electrode trench and electrically insulated from the drift region by a gate dielectric layer arranged between the gate electrode and the drift region. The field electrode needle trench is laterally spaced from the gate electrode trench and extends into the drift region. The field electrode needle trench includes a field electrode arranged in the field electrode needle trench and electrically insulated from the drift region by a cavity formed between the field electrode and the drift region.

In some aspects of the invention, an n-type field-stop layer can have a total impurity of such an extent that a depletion layer spreading in response to an application of a rated voltage stops inside the n-type field-stop layer together with the total impurity of an n.sup. type drift layer. Also, the n-type field-stop layer can have a concentration gradient such that the impurity concentration of the n-type field-stop layer decreases from a p.sup.+ type collector layer toward a p-type base layer, and the diffusion depth is 20 m or more. Furthermore, an n.sup.+ type buffer layer of which the peak impurity concentration can be higher than that of the n-type field-stop layer at 610.sup.15 cm.sup.3 or more, and one-tenth or less of the peak impurity concentration of the p.sup.+ type collector layer, can be included between the n-type field-stop layer and p.sup.+ type collector layer.

An SiC semiconductor device has a p type region including a low concentration region and a high concentration region filled in a trench formed in a cell region. A p type column is provided by the low concentration region, and a p.sup.+ type deep layer is provided by the high concentration region. Thus, since a SJ structure can be made by the p type column and the n type column provided by the n type drift layer, an on-state resistance can be reduced. As a drain potential can be blocked by the p.sup.+ type deep layer, at turnoff, an electric field applied to the gate insulation film can be alleviated and thus breakage of the gate insulation film can be restricted. Therefore, the SiC semiconductor device can realize the reduction of the on-state resistance and the restriction of breakage of the gate insulation film.

An improvement is achieved in the performance of a semiconductor device. The semiconductor device includes a first trench gate electrode and second and third trench gate electrodes located on both sides of the first trench gate electrode interposed therebetween. In each of a semiconductor layer located between the first and second trench gate electrodes and the semiconductor layer located between the first and third trench gate electrodes, a plurality of p.sup.+-type semiconductor regions are formed. The p.sup.+-type semiconductor regions are arranged along the extending direction of the first trench gate electrode in plan view to be spaced apart from each other.

A gate-all around fin double diffused metal oxide semiconductor (DMOS) devices and methods of manufacture are disclosed. The method includes forming a plurality of fin structures from a substrate. The method further includes forming a well of a first conductivity type and a second conductivity type within the substrate and corresponding fin structures of the plurality of fin structures. The method further includes forming a source contact on an exposed portion of a first fin structure. The method further comprises forming drain contacts on exposed portions of adjacent fin structures to the first fin structure. The method further includes forming a gate structure in a dielectric fill material about the first fin structure and extending over the well of the first conductivity type.

The surface of an interlayer insulating film formed over an emitter coupling portion and the surface of an emitter electrode formed over the interlayer insulating film are caused to have a gentle shape, in particular, at the end of the emitter coupling portion, by forming the emitter coupling portion over a main surface of a semiconductor substrate and integrally with trench gate electrodes in order to form a spacer over the sidewall of the emitter coupling portion. Thereby, stress is dispersed, not concentrated in an acute angle portion of the emitter coupling portion when an emitter wire is coupled to the emitter electrode (emitter pad), and hence occurrence of a crack can be suppressed. Further, by forming the spacer, the concavities and convexities to be formed in the surface of the emitter electrode can be reduced, whereby the adhesiveness between the emitter electrode and the emitter wire can be improved.

Apparatus and associated methods relate to an edge-termination structure surrounding a high-voltage MOSFET for reducing a peak lateral electric field. The edge-termination structure includes a sequence of annular trenches and semiconductor pillars circumscribing the high-voltage MOSFET. Each of the annular trenches is laterally separated from the other annular trenches by one of the semiconductor pillars. Each of the annular trenches has dielectric sidewalls and a dielectric bottom electrically isolating a conductive core within each of the annular trenches from a drain-biased region of the semiconductor pillar outside of and adjacent to the annular trench. The conductive core of the innermost trench is biased, while the conductive cores of one or more outer trenches are floating. In some embodiments, a surface of an inner semiconductor pillar is biased as well. The peak lateral electric field can advantageously be reduced by physical arrangement of trenches and electrical biasing sequence.

A wide band gap semiconductor device includes a semiconductor layer, a trench formed in the semiconductor layer, first, second, and third regions having particular conductivity types and defining sides of the trench, and a first electrode embedded inside an insulating film in the trench. The second region integrally includes a first portion arranged closer to a first surface of the semiconductor layer than to a bottom surface of the trench, and a second portion projecting from the first portion toward a second surface of the semiconductor layer to a depth below a bottom surface of the trench. The second portion of the second region defines a boundary surface with the third region, the boundary region being at an incline with respect to the first surface of the semiconductor layer.