| 摘要 |
PURPOSE:To obtain a high reliability FET which has a required channel length in good reproductivity by preventing etching under a gate electrode, providing a mask on the side wall of the gate electrode on an insulation film. CONSTITUTION:An n<-> poly-Si thin film 2, an SiO2 layer 3 and a conductive poly-Si 4 are piled on a glass plate 1, the conductive layer 4 is etched, using a resist mask 5, and a gate electrode 6 W wide is made. A mask 20 is made on the side surface of the electrode 6 by RIE often covering with a photoresist 21. The formation of a bottom under the gate electrode 6 is prevented by isotropically etching with HF selecting the thickness T of the mask 20 and the width Ws of a gate insulation film 7. N<+> diffusion layers 2s, 2d; n<-> channel 2c are made by covering with a PSG 9 often removing resists 5, 7. Electrodes 10s, 10d are attached by opening a window on the PSG 9. This construction enables to avoid the unnecessary and unstable side surface etching of the gate insulation film, to effectively prevent unstable short channeling and to obtain a high reliability FET in good reproductivity. |
