| 摘要 |
PURPOSE:To heighten gate breakdown voltage, by continuing isotropic etching after providing a semiconductor substrate with a V-shape groove by anisotropic etching. CONSTITUTION:A p-epitaxial-layer is laminated on an n-type Si substrate, surface oxide film is etched by using a nitride film mask, and by making selective oxidation after B ion is driven in, a field oxide film 107 and a p-type reversion-preventing layer 106 are formed. It is again photo-etched and As ion is injected into thus exposed substrate to form an n<+>-layer 108 and to cover with an oxide film 109. Nitride film and oxide film in channel section are removed and etched anisotropically. As the V-shape groove's tip is sharp, dielectric resistance of the gate film is extremely deteriorated, and therefore, the tip is rounded by isotropic etching. And then, a gate oxide film 112 and a gate electrode 113 are provided and covered with PSG114, and an Al electrode 115 is provided. It is possible, in this mechanism, to prevent electric field from gathering to the V-shape groove's tip and to raise the gate film's dielectric resistance to an extremely high value. |
