| 摘要 |
PURPOSE: To provide a technique capable of realizing a mushroom gate for satisfying simultaneously demanded condition of low electric resistance to a necessarily thinly constituted gate as the gate of a high-frequency field effect transistor. CONSTITUTION: Three masking layers 9, 10 and 11 are deposited to the main body of a semiconductor of a transistor, and at least two of the masking layers are different and selectively dissolved. After the opening of an outer layer, an intermediate layer 10 is sub-etched which is related to the outer layer and dissolved. Then, a base of a gate is etched at the inner layer 11. The edge of sub-etching prevents metal which has been deposited on a mask from being adhered to the gate. Thus, the lift-off of the mask is facilitated. In may be applied to a microwave transistor provided with a symmetrical or asymmetrical mushroom gate.
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