Nanometer-scale characterization of layer-by-layer oxidation of Si surfaces

摘要

The oxidation of Si surfaces is an important issue in the technologicl application of Si-based mciroelectronics, such as metal-oxide-semiconductor field-effect transistors (MOSFETs). As the sizes of individual devices are scaled down, the semiconductor industry will demand ultrathin gate oxides that are less than 2 nm thick. This oxide thickness corresponds to oxidation of less than ten monolayers of Si(001) substrates, so we need to understand the initial oxidation process and the ability to control the reaction for further device development. Recently, several groups have reported layer-by-layer oxidation of Si surfaces by using TEM and XPS techniques [1-3]. This oxidaton form has attracted a great deal of attention, because it is ideal for attaining atomic scale uniformity in ultrathin gate oxides.