Nitrogen in-situ doped poly buffer LOCOS: simple and scalable isolation technology for deep-submicron silicon devices

This paper describes a novel LOCOS (LOCal Oxidation of Silicon) technology that uses nitrogen in-situ doped amorphous-Si as a buffer layer instead of the undoped poly-Si used in conventional Poly Buffered LOCOS (PBL). This technology makes it possible to use a thin 6-nm pad oxide by preventing the formation of voids in Si buffer layer and improves edge morphology and effective dimension loss. Therefore, the technology will be used in advanced LSI fabrication with KrF lithography, notwithstanding that the number of processing steps is the same as conventional PBL. This new LOCOS technology is the most promising isolation technology for the deep-submicron era due to its simplicity and scalability.