| 摘要 |
PURPOSE:To shorten gate length sufficiently, and to increase the speed of signal transmission by forming a nitride film to the whole substrate by using an ECRCVD method, etching an oxide film and exposing a substrate surface in a section abutting on a gate through selective etching, which does not work to the nitride film. CONSTITUTION:An operating layer 2 is shaped onto a semi-insulating GaAs substrate 1 in the same manner as a heat-resistant gate method. Nitride film SiN 3 is formed through an ECRCVD method, employing a dummy gate by a photoresist 52 as a mask anew. N-type impurity ions such as Si<+> ions are implanted through the nitride film 3 to obtain high-concentration impurity regions 4 at two positions. The dummy gate 52 is removed through a lift-off method. The whole substrate 1 is coated with oxide-film SiO2 5, and implanted ions are activated through heat treatment. Windows are bored to both the oxide film 5 and the nitride film 3, and source and drain electrode metals 6, 6 are shaped. Only the oxide film 5 in a gate section is etched selectively by a photoresist 53. Accordingly, a gate electrode metal 8 is formed to the operating layer 2 exposed in a self-alignment manner.
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