| 摘要 |
PURPOSE:To enable quick supply of products in response to the ROM code request of a user, by firstly turning all N channel memory cell Tr's into a depletion state, and ion-implanting boron after gate electrode polysilicon is formed. CONSTITUTION:Phosphorus diffusion region 4 is formed by implanting about 10<13>-10<14> phosphorus ions with an ion implanting machine; then gate electrode polysilicon 5 of a transistor is formed; after resist 6 is applied to the region except the part to be implanted, the source.drain 7 of an N channel memory cell Tr is formed by implanting phosphorus of about 10<15> with the ion implanting machine; resist 6 is applied by a photolithography method on the region except an N channel memory cell Tr to be selected; a phosphorus boron diffused region 8 of high boron concentration is formed by implanting 10<14>-10<15> high energy boron ions with the ion implanting machine, and turned into an enhancement state. |
