Ozone based high-temperature atomic layer deposition of SiO ₂ thin films

Abstract

Abstract In this paper, atomic layer deposition of SiO 2 thin films was investigated with Si 2 Cl 6 and O 3 /O 2 (400 g m −3 ). O 3 /O 2 is not preferred for high-temperature (>400 °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 °C in comparison with O 2 and H 2 O. The ALD of SiO 2 films was examined at deposition temperatures from 500 °C to 700 °C. The growth rate at 600 °C was saturated to 0.03 nm/cycle with Si 2 Cl 6 exposure over 1.2 × 10 5 L. O 3 /O 2 also showed ALD-like saturation behaviors for exposures over 2.4 × 10 6 L. The ALD films deposited at 600 °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 SiO 2 deposited at 250 °C and LPCVD SiO 2 deposited at 450 °C.