Method of making a contact programmable double level polysilicon MOS read only memory

摘要

A contact programmable, small cell area MOS read only memory or ROM is formed by a process compatible with standard N-channel silicon gate manufacturing methods. Address lines are metal, gates are second level polysilicon, and output and ground lines are defined by elongated N+ regions. Each potential MOS transistor in the array is programmed to be a logic "1" or "0", by presence or absence of a contact engaging the polysilicon gate over the thin gate oxide.