Low-temperature formation of device-quality SiO2/Si interfaces by a two-step remote plasma-assisted oxidation/deposition process

This article describes a new approach to the low-temperature (200–300 °C) formation of electronic-quality SiO2/Si heterostructures in which the steps of interface formation and bulk oxide deposition are separately controlled to optimize the electronic properties of the resulting device structure. This approach combines an in vacuo cleaning/passivation step for removal of residual C-atom surface contamination with a passivation of the Si surface by an ultrathin oxide layer, ∼0.5 nm, and then completes the SiO2/Si heterostructure with a plasma-assisted deposition of the SiO2 thin film. The new process differs both qualitatively and quantitatively from conventional high-temperature, ∼850–1000 °C, thermal, or rapid thermal oxidation in which interface formation and oxide film growth are accomplished at the same time through a continuous consumption of the Si substrate.