Low temperature deposition of silicon nitride using Si3Cl8

Abstract

We demonstrate the deposition of SixNy thin films using octachlorotrisilane (Si3Cl8) and ammonia between 300 and 500°C by an atomic layer deposition-like growth mechanism. Although there are chemical vapor deposition growth mechanisms present, which lead to an incomplete saturation, a step coverage >80% in high aspect ratio (>60:1) trenches could be achieved. The deposited films oxidize after contact with ambient air leading to substoichiometric N/Si ratios. Increasing the deposition temperature diminishes this oxidation. At temperatures >390°C a bulk N/Si ratio of ~1.3 is achieved. The capacitance–voltage (C–V) measurements of these films yield a k value of ~6 and a strong C–V hysteresis indicates significant charge trapping.