Device-Quality SiO2/Si(100) Interfaces Prepared by a Two-Step Remote Plasma-Assisted Oxidation-Depositon Process

Abstract
When using conventional high-temperature thermal oxidation processes to fabricate Si-based devices that include SiO2 dielectrics, the SiO2/Si interface and bulk-oxide layer are formed at the same time. We have developed a new low-temperature process that separates interface formation, by plasma-assisted oxidation, from bulk-oxide deposition, by plasma-assisted chemical-vapor deposition (CVD) and thereby separately controls, and optimizes the respective electrical properties of the SiO2/Si interface, and the SiO2 layer. This approach has been extended to multilayer oxide-nitride-oxide (ONO) dielectrics on Si substrates, and has also been successfully transferred to an integrated processing cluster tool that combines the new SiO2/Si oxidation/deposition process, with deposition of polycrystalline Si gate electrodes by a high-temperature, rapid thermal CVD process to form a stacked gate structure.