| 摘要 |
PURPOSE:To improve the withstand voltage of a gate electrode by forming a gate oxide film and a gate electrode in combination with a dry oxidation and a lift-off process and eliminating the undercut of the film. CONSTITUTION:A field oxide film 2 is formed by LOCOS process on a P type semiconductor substrate 1, and a thin oxide film 10 is formed thereon. Then, a negative photoresist 11 is covered thereon, and a reverse pattern is formed thereon. Subsequently, the substrate 1 is set in a heated reaction container, hydrofluoric acid gas is introduced thereinto under reduced pressure, and a thin oxide film 10 directly under the resist film 11 is etched. Thereafter, a polysilicon layer 14 is covered thereon, the resist 11 is concurrently removed by a lift-off process, and a gate electrode is formed. Then, a PSG film 5 is covered, and source, drain layer 6 and source and drain electrodes 7 are formed. |
