| 摘要 |
PROBLEM TO BE SOLVED: To provide a field-effect transistor having a high electrostatic breakdown voltage, and a manufacturing method thereof. SOLUTION: In this embodiment, a gradient angle of a mesa step in a field- effect transistor is gently tapered without exceeding 45 deg.. The mesa step is formed by dry-etching using a tapered shape of a resist. After the resist is coated on a semiconductor, a pattern is formed by exposure. Although the resist is formed vertically at this time, it is heat-treated, for example, at 130 to 150 deg.C so that a tapered angle is formed not exceeding 60 deg.. Then, the semiconductor layer part is etched 0.2μm by dry-etching. Depending on the difference in etching rate of the resist, the mesa step having the height of approximately 0.2μm and the gradient angle of approximately 35 deg. is formed.
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