Experimental study of the electrical performance of isolation structures

Abstract

The electrical behavior of the parasitic AI-gate MOS transistor on LOCOS and SILO isolation structures is investigated. The influence of the two-dimensional parasitic channel on the isolation performances is pointed out by studying the bird's beak length, the field oxide thickness, and the use of a semi-or fully recessed structure. The measured characteristics are discussed and explained with the assistance of the two-dimensional process simulations of the isolation structures.

A Bird's‐Beak‐Free Sealed‐Interface Local Oxidation Technology for Submicron Ultra‐Large‐Scale Integrated Circuits

“…In this mode, the interface between silicon and silicon nitride is sealed, shutting off lateral diffusion of oxidizing species and eliminating the usual bird's beak. To form a sandwich isolation mask, the use of LPCVD SiBN4 (10 nm), CVD SiO2 (30 nm), and LPCVD SiBN4 (150 nm) has already been reported (18)(19). Those works (18)(19) could not produce an ideal bird'S-beak-free isolation technology due to several associated disadvantages in depositing ultrathin films of SiBN4 and SiO2.…”

“…To form a sandwich isolation mask, the use of LPCVD SiBN4 (10 nm), CVD SiO2 (30 nm), and LPCVD SiBN4 (150 nm) has already been reported (18)(19). Those works (18)(19) could not produce an ideal bird'S-beak-free isolation technology due to several associated disadvantages in depositing ultrathin films of SiBN4 and SiO2. Also, composite mask formation was done by depositing thin films in three separate steps, which generated more defects due to impurity trapping between the layers 9 Since SiBN4-I was deposited at higher temperature, required film uniformity and repeatability are rather difficult.…”