| 摘要 |
PURPOSE:To obtain an FET having a high gate withstand voltage by a method wherein an easily oxidizable pure metal is used as a gate material, and is covered with a well-known oxidation resisting material. CONSTITUTION:A W layer 3 and a poly-Si layer 4 added with P are deposited on a gate oxide film 2 on a P type Si substrate 1 provided with a channel layer 5 to resist channeling, and to let have gettering action. Plasma etching is performed applying a resist mask 9, the mask 9 is removed, and P ions are implanted at low concentration to form layers 6. The surface is covered with a poly-Si layer 7 added with P, and anisotropic etching is performed to leave the layers 7 only on the sides of the W layer 3. Then the remaining oxide films 2 on the surface of the Si substrate are etched to be removed, and the surface is covered newly with a thermal oxide film 2. As ions are implanted at high concentration through the film 2. According to this construction, even when easily oxidizable W, Mo, Co, Ni,Ir, Rh, etc., are used for a gate electrode, oxidation can be checked by covering with the material of poly-Si, Si3N4, a CVD oxide film, etc., and the FET having the high gate withstand voltage can be obtained. |
