Formation of Si/SiO2 Heterostructures by Low-Temperature, Plasma-Assisted Oxidation and Deposition Processes

A new approach to the low-temperature, < 500°C, formation of SiO2/Si heterostructures formed by plasma-assisted processing is discussed. Following an ex-situ RCA clean, Si(100) wafers are exposed to O-atoms generated in a remote plasma. This: i) eliminates residual C-atom contamination; and ii) forms a thin oxide layer, ~0.5–0.6 nm. SiO2/Si heterostructures are completed by remote PECVD deposition of an oxide film ~15 nm thick. The Si02/Si interface and bulk oxide electrical properties of MOS devices are similar to those of devices with thermal oxides grown at ~1000°C. This paper: i) compares the use of pre-deposition H-atom and O-atom treatments, prior to oxide deposition; and ii) discusses changes in electrical properties, when composite oxide/nitride dielectrics are prepared by sequential oxide and nitride remote PECVD depositions.