VOID FORMATION AT SILICON-NITRIDE SILICON INTERFACES STUDIED BY VARIABLE-ENERGY POSITRONS

Variable-energy positrons (VEP) were used to study the depth distribut ion of defects in SiN(x)/Si structures fabricated using ditertiary but yl silane (CONSI 4000) as the silicon precursor in an electron cyclotr on resonance plasma chemical vapor deposition system. Films were grown to thickness ranging from 500 to 3500 angstrom at substrate temperatu res between room temperature and 400-degrees-C and under various plasm a conditions. The VEP results give evidence for differing concentratio ns of very large open-volume defects at several of the SiN(x)/Si inter faces, confirmed by transmission and scanning electron microscopy. The ir presence was correlated with non-reactive organosilicon adsorption on the substrates prior to the thin film deposition.