Radiation hardened field oxides for NMOS and CMOS-bulk and process for forming

摘要

The field oxide surrounding an NMOS device or the field oxide around the NMOS device and between the NMOS and PMOS devices in CMOS is split or notched to make at least one thin field oxide region under which a degenerative P+ region is formed in the substrate to increase threshold voltages of the undesired field oxide FET.