SEMICONDUCTOR DEVICE AND SEMICONDUCTOR DEVICE MANUFACTURING METHOD

摘要

A MOS gate structure including a p base region, a p epitaxial layer, an n++ source region, a p+ contact region, an n inversion region, a gate insulating film, and a gate electrode and a front surface electrode are provided on the front surface of an epitaxial substrate obtained by depositing an n− epitaxial layer on the front surface of a SiC substrate. A first metal film is provided on the front surface electrode so as to cover 10% or more, preferably, 60% to 90%, of an entire upper surface of the front surface electrode. The SiC-MOSFET is manufactured by forming a rear surface electrode, forming the first metal film on the surface of the front surface electrode, and annealing in a N2 atmosphere. According to this structure, it is possible to suppress a reduction in gate threshold voltage in a semiconductor device using a SiC semiconductor.

主权项

1. A semiconductor device manufacturing method, comprising the steps of:
(a) forming an insulated gate structure including a gate insulating film and a gate electrode on a front surface of a silicon carbide substrate, with an interlayer insulating film covering the gate electrode; (b) forming a front surface electrode on the front surface of the silicon carbide substrate so as to be insulated from the gate electrode by the interlayer insulating film; (c) forming, on the front surface electrode, a covering film consisting of a metal film or a lamination of plural metal films; and (d) after step (c), annealing the silicon carbide substrate in a vacuum or in a gas atmosphere including nitrogen gas, a mixed gas including nitrogen gas, or argon gas.