Formation of device quality Si/SiO2 interfaces at low substrate temperatures by remote plasma enhanced chemical vapor deposition of SiO2

Abstract

We discuss the factors that contribute to the formation of device quality Si/SiO2 interfaces using the low temperature process of remote plasma enhanced chemical vapor deposition (PECVD) to deposit the SiO2 thin films. This includes identification of: (i) the ex situ and in situ processes required for surface preparation prior to film deposition; (ii) the factors that define the range of substrate temperatures for thin film deposition; and (iii) the factors that are important in post-deposition annealing of Si/SiO2 interfaces. The low temperature limit for SiO2 deposition by remote PECVD derives from increased SiOH incorporation, whereas the high temperature and thickness limitations derive from subcutaneous surface reactions in which the Si substrate can be oxidized via process gas/substrate reactions during the deposition process.