Self-aligned contact process for complementary field-effect integrated circuits

摘要

A method for making a NMOS self-aligned contact in CMOS circuits without an extra mask is described. The maskless contact technique makes use of the fact that the blanket N-type implant, self-aligned to exposed field-oxide edge, will not change the P+ diffusion to N-type. The net P+ concentration in the contact region is reduced slightly but does not degrade the PMOS device performance.