Integration of poly buffered LOCOS and gate processing for submicrometer isolation technique

A modified poly buffered LOCOS (PBL) process is described which simplifies processing and provides advantages over conventional PBL and LOCOS processes. The use of a poly buffer between the pad oxide and the nitride layer offers the opportunity of integrating the poly gate deposition and the field isolating process and overcomes the processing difficulties of the conventional PBL while maintaining the advantage of a narrow spacing between active areas (THINOX). The process sequence of the conventional PBL and the integrated PBL (IPBL) process are summarized.