| 摘要 |
PROBLEM TO BE SOLVED: To increase the breakdown strength of power semiconductor transistors and lower the loss by a method wherein an AlN layer which comes into contact with a conductive layer of SiC and has a lattice constant, or its mixed crystal is epitaxially grown to form a superior interface with a few interface levels, and an electrode for controlling a current is provided in its upper part. SOLUTION: A buffer layer 12 is epitaxially grown on a semi-insulated SiC substrate 11, and a p type conductive layer 13 and an n type layer 14 for a source electrode 16 and a drain electrode 17 are grown. Thereafter, a part forming a gate electrode 18 is etched up to the p type conductive layer 13, and the AlN insulator film 14 is deposited by a MOCVD method to form the source electrode 16, the drain electrode 17, and the gate electrode 18. In an interface level between an insulator film 15 and the p type conductive layer 13, lattice mismatch between SiC and AlN is small and also the AlN layer is epitaxially grown at high temperature. Therefore, it is possible to obtain a superior interface with a uniform film thickness and a few interface levels. For this reason, if a positive potential is applied to a gate electrode, there occurs an inverted layer 19 near the interface in which electrons are stored.
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