Plasma Enhancement in Direct Nitridation of Silicon and Silicon-Dioxide

Abstract

Effects of plasma on direct nitridation of Si and Si0 2 have been investigated. The reactor consisted of a quartz tube, SiC-coated carbonsusceptors and an RF-induction coil. The electrical probe technique was used to detect floating potential of the susceptor having Si substrates. The voltage distribution between the susceptor and plasma is influenced by nitridation ambient, pressure, reactor geometry and RF power. The predominant species in NH 3 plasma is NH radicals which are thought to be negatively charged in an ion sheath formed around the susceptor. The Cabrera-Mott model has been successfully applied to analyze the nitridation mechanism. Plasma enhancement is mainly caused by activation of characteristic velocity of nitridation species rather than by an increase in the electric field appearing in a film. Enhancement due to fluorine incorporation is also explained with the model. Bombardment of ionic species causes sputtering and deposition resulting in damage, contamination and thickness nonuniformity. Optimizing the plasma conditions, decrease in nitridation temperature, increase in growth rate, and improvements in film composition and interfacial structure have been obtained. It has been found that the further nitridation proceeds, the lower Nss becomes. This technique offers various advantages to the VLSI dielectric process.

Study of the mechanisms of GaN film growth on GaAs surfaces by thermal and plasma nitridation

“…15͒ and nitridation of silicon, 30 has also been considered. at high temperature ͑route I͒, through the thermal decomposition of GaAs ͑GaAs decomposition threshold is about 550°C͒, yielding free Ga and As, which in turn react with N atoms, i.e., the ''thermal decomposition route;'' II.…”