| 摘要 |
In a method of forming a gate recess, on a surface of an epitaxial wafer including an epitaxial substrate, having a semiconductor layer having the band gap energy varying therein in the depth-wise direction, and a SiN surface protective layer, having a sidewall forming a gate opening and coating the surface of the epitaxial substrate, ultraviolet light having its energy equivalent to the band gap energy of the specific semiconductor layer is irradiated, while the specific semiconductor layer is photoelectrochemically etched from the gate opening with the SiN surface protective layer used as a mask. The gate recess free from plasma ion-induced damage is thus obtained.
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