| 摘要 |
PURPOSE:To simplify the steps of manufacturing the semiconductor device by conducting the introduction of impurity by a special method, thereby raising the withstand voltage at a part of enhancement type and depletion type transistor and forming them on the same semiconductor substrate. CONSTITUTION:A field oxide film 4 for isolating respective transistors is formed on the surface of a P type silicon semiconductor substrate 2, the surface of the substrate 2 is oxidized, a gate oxide film 6 is formed thereon, and boron ion is implanted to the whole surface through the film 6. Then, a resist 10 is coated on the film 6, with a mask it is patterned by a photographic process, and there are formed the window 30 for D-Tr gate, the window 32 for off-set gate of high withstand E-Tr and window 34 for control and off-set gate of the high withstand voltage D-Tr. Then, phosphorus ion is implanted through the respective windows, surface layers 36, 38, 40 are thus formed, and drain current controlling and off-setting gate impurities are simultaneously implanted. |
