Ozone based high-temperature atomic layer deposition of SiO2 thin films

Abstract

In this paper, atomic layer deposition of SiO2 thin films was investigated with Si2Cl6 and O-3/O-2 (400 g m(-3)). O-3/O-2 is not preferred for hightemperature (>400 degrees C) processes due to its lower decomposition temperature, especially in a furnace-type chamber. However, with Si oxidation test using a cold-wall chamber, we have demonstrated the reactivity of O-3/O-2 up to 800 degrees C in comparison with O-2 and H2O. The ALD of SiO2 films was examined at deposition temperatures from 500 degrees C to 700 degrees C. The growth rate at 600 degrees C was saturated to 0.03 nm/cycle with Si2Cl6 exposure over 1.2 x 10(5) L. O-3/O-2 also showed ALD-like saturation behaviors for exposures over 2.4 x 10(6) L. The ALD films deposited at 600 degrees C exhibited relatively smooth surface roughness (<0.18 nm) and low wet etch rate (1.6 nm min(-1), 500:1 HF) that are comparable with PECVD SiO2 deposited at 250 degrees C and LPCVD SiO2 deposited at 450 degrees C.