| 摘要 |
PURPOSE:To prevent a contact between an impurity and a gate electrode even when the ions of the impurity are implanted and the impurity is diffused in the lateral direction, and to obviate the lowering of gate withstanding voltage by bringing the end section of the gate electrode consisting of a metallic film or an alloy thin-film inside the end section of a thin-film on the end section of the gate electrode. CONSTITUTION:An n-type layer 2 is formed onto a semi-insulating gallium arsenide substrate 1, a tantalum-tungsten silicide film is deposited, and an silicon dioxide film 5 is further grown on the silicide film in a vapor phase. When the film 5 is etched in an anisotropic manner and the tantalum-tungsten silicide film 3 is plasma-etched in an isotropic manner, the end section of the film 3 is brought to the side inner than the end section of the silicon dioxide film 5. Silicon ions are implanted, and high-concentration n-type layers 4 are shaped through heat treatment. Accordingly, since the end section of a gate electrode is brought to the side inner than the end section of the silicon dioxide film on the end section of the gate electrode, implantation layers are not brought into contact with the gate electrode even when the ions of an impurity are implanted and the implantation layers are diffused in the lateral direction, thus preventing the lowering of gate withstanding voltage.
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