Cultivation of ornamental fruit

摘要

The method improves electrical characteristic of programmed cell of the mask ROM, MOS transistor is formed by implanting impurity ions of second conduction type on a semiconductor substrate of first conduction type through a gate insulation film, forming a gate electrode by selectively etching polysilicon and tungsten silicide formed thereon, and diffusing impurity ions of second conduction type so as to form source/drain region. Photoresist covers a part of MOS transistor excepting the selective photoetched MOS transistor, and impurity ions are implanted in the gate insulation film through side wall of the gate electrode of the MOS transistor. An interlayer insulation film covers the resulting structure after removing the photoresist, contact hole is formed in the interlayer insulation film, and formation of protective layer and opening of pad are carried out.