IGBT using trench gate electrode

摘要

An IGBT includes a trench gate electrode that is bent when a semiconductor substrate is seen in a plan view, and an inner semiconductor region of the same conductivity type as an emitter region is formed at a position inside a bent portion of the trench gate electrode and exposed on a front surface of the semiconductor substrate. The trench gate electrode is bent, and therefore, a hole density during operation increases, whereby conductivity modulation phenomenon is accelerated, and an on-state voltage is reduced. When the IGBT is turned off, the inner semiconductor region influences a movement path of the holes so that a moving distance thereof through a body region becomes short. The holes escape easily to a body contact region when the IGBT is turned off. Increase of current density during the operation and prevention of a latchup are both achieved.

主权项

1. An IGBT comprising:
a semiconductor substrate; an emitter electrode formed on a front surface of the semiconductor substrate; and a collector electrode formed on a back surface of the semiconductor substrate, wherein the semiconductor substrate comprises: an emitter region exposed on the front surface of the semiconductor substrate; a collector region exposed on the back surface of the semiconductor substrate; a body region contacting the emitter region and extending deeper than the emitter region; a drift region separating the body region and the collector region; and a body contact region exposed on the front surface of the semiconductor substrate, the semiconductor substrate being formed with: a trench extending from the front surface of the semiconductor substrate and reaching the drift region; a gate insulating film covering a wall of the trench; and a trench gate electrode filled in the trench, the trench gate electrode faces the emitter region, the body region, and the drift region in this order via the gate insulating film, the emitter region and the body contact region are configured to be electrically connected to the emitter electrode, the trench gate electrode is insulated from the emitter electrode, the collector region is configured to be electrically connected to the collector electrode, the trench gate electrode is bent when the semiconductor substrate is seen in a plan view, an inner semiconductor region of the same conductivity type as the emitter region is formed at a position inside a bent portion of the trench gate electrode and exposed on the front surface of the semiconductor substrate, and the inner semiconductor region is not configured to become electrically connected to the emitter electrode.