| 摘要 |
PURPOSE:To obtain a stable gate electrode having excellent adhesion by constituting a gate electrode of three phases by using a high melting-point metallic layer as a first layer, a high electric conduction layer as a second layer and a high melting-point metallic layer as a third layer. CONSTITUTION:An opening is bored to an insulating film 17 through dry etching in order to limit gate length (a) to submicron. A first high melting-point metallic layer 13 in a gate electrode 16 formed onto the insulating film 17 has excellent adhesion to both the insulating film 17 and a GaAs substrate 11, stable Schottky characteristics having high heat resistance are acquired, and Mo, W, Ta, Ti and these alloys or these silicides are employed as the high melting-point metallic layer 13. A high electric conductivity layer 14 used as a second layer functions as the lowering of gate resistance, Au, Ag, Cu, Al are employed as the layer 14, and a second high melting-point metallic layer 15 used as a third layer fills the role of a mask material for obtaining a high selection ratio when dry-etching the gate electrode 16. Accordingly, the electrical characteristics and mechanical strength of the gate electrode are improved.
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