A power semiconductor device includes trenches disposed in a first base layer of a first conductivity type at intervals to partition main and dummy cells, at a position remote from a collector layer of a second conductivity type. In the main cell, a second base layer of the second conductivity type, and an emitter layer of the first conductivity type are disposed. In the dummy cell, a buffer layer of the second conductivity type is disposed. A gate electrode is disposed, through a gate insulating film, in a trench adjacent to the main cell. A buffer resistor having an infinitely large resistance value is inserted between the buffer layer and emitter electrode. The dummy cell is provided with an inhibiting structure to reduce carriers of the second conductivity type to flow to and accumulate in the buffer layer from the collector layer.

Power semiconductor device

Self-aligned trench MOSFETs and methods for manufacturing the same are disclosed. By having a self-aligned structure, the number of MOSFETS per unit area—the cell density—is increased, making the MOSFETs cheaper to produce. The self-aligned structure for the MOSFET is provided by making the sidewall of the overlying isolation dielectric layer substantially aligned with the sidewall of the gate conductor. Such an alignment can be made through any number of methods such as using a dual dielectric process, using a selective dielectric oxidation process, using a selective dielectric deposition process, or a spin-on-glass dielectric process.

Self-aligned trench mosfets and methods for making the same

Edge termination for a silicon carbide Schottky rectifier is provided by including a silicon carbide epitaxial region on a voltage blocking layer of the Schottky rectifier and adjacent a Schottky contact of the silicon carbide Schottky rectifier. The silicon carbide epitaxial layer may have a thickness and a doping level so as to provide a charge in the silicon carbide epitaxial region based on the surface doping of the blocking layer. The silicon carbide epitaxial region may form a non-ohmic contact with the Schottky contact. The silicon carbide epitaxial region may have a width of from about 1.5 to about 5 times the thickness of the blocking layer. Schottky rectifiers with such edge termination and methods of fabricating such edge termination and such rectifiers are also provided. Such methods may also advantageously improve the performance of the resulting devices and may simplify the fabrication process.

Epitaxial edge termination for silicon carbide Schottky devices and methods of fabricating silicon carbide devices incorporating same

Edge termination for silicon carbide devices has a plurality of concentric floating guard rings in a silicon carbide layer that are adjacent and spaced apart from a silicon carbide-based semiconductor junction. An insulating layer, such as an oxide, is provided on the floating guard rings and a silicon carbide surface charge compensation region is provided between the floating guard rings and is adjacent the insulating layer. Methods of fabricating such edge termination are also provided.

Multiple floating guard ring edge termination for silicon carbide devices

The specification describes Schottky barrier devices with distributed guard rings. In one embodiment the guard ring only partially overlaps the barrier. In another embodiment the guard ring is spaced from the barrier throughout, but separated by an MOS gate so that the guard ring and barrier are connected at low bias by an inversion layer.

Schottky diode guard ring structures

A guard-ring-equipped Schottky barrier diode, which can have shortened reverse recovery time and increased withstand voltage, has a Schottky barrier layer (27) formed on a semiconductor substrate (20) of a first conductivity type and a guard ring (25), which has a second conductivity type, formed on surface of the substrate (20) isolated from but surrounding the periphery of the barrier layer (27). An insulative film (23) with an opening over part of the guard ring (25) is formed over the region between the edge of the Schottky barrier layer (27) and the guard ring (25). A high-resistance layer (26) is formed on this opening and is connected with the Schottky barrier layer (27) by a metal electrode (28). The size of the area between the guard ring (25) and the end ofthe barrier layer (27) is less than the sum of the widths of the depletion layers of the guard ring (25) and the barrier layer (27) at the time when the lower voltage of either the barrier layer (27) breakdown voltage or the guard ring (25) breakdown voltage is applied.

Schottky barrier diode with guard ring

A reverse conducting gate-turnoff thyristor includes a switching device section, a diode section, and an isolating section located between the switching device section and the diode section. The isolating section includes an impurity layer formed by controlling impurity diffusion and having an impurity concentration lower than those of the switching device section and the diode section.

Susumu Iesaka

Papers

Schottky barrier diode with guard ring

Reverse conducting gate-turnoff thyristor