Study on residual OH content in low-temperature Si oxide films after in situ post-deposition heating (PDH)

Abstract

We investigated the post-deposition heating (PDH) effect on OH content in SiOx films deposited by atmospheric-pressure CVD using a deposition source of silicone oil (SO) with O3 and TCE vapor at a temperature T d of 180 °C–250 °C. The PDH is performed in situ for 5 min in the deposition chamber just after film deposition without any supply of SO, where the heating temperature is the same as T d. The OH content in the films deposited normally decreases with increasing T d. In contrast, those with PDH decrease with deceasing T d from 220 °C, and, at T d = 190 °C, a minimum OH content can be obtained. This means that lower OH content remains at a lower deposition temperature. The PDH effect on OH reduction can be explained by easily reconstructible structure of SiOx films deposited at low temperature. Furthermore, we discuss the mechanism of the PDH effect from other points of view.