Characterization of ultrathin SiO2/Si interface grown by low temperature plasma oxidation

摘要

＜正＞ Ultrathin SiO2 layers on Si （100） wafers were prepared by plasma oxidation at a low temperature （250℃） . The analyses of X-ray photoelectron spectroscopy （XPS） and TEM reveal that the chemical composition of the oxide layer is stoichiometric SiO2 and the SiO2/Si interface is abrupt. The thickness of the ultrathin oxide layer obtained from XPS, capacitance-voltage （C-V） and ellipsometry measurements indicate a nonlinear time dependence. The high frequency C-V characterization of MOS structure shows that the fixed charge density in SiO2film is about 1011 cm-2. It is also shown that the strength of breakdown electrical field of SiO2 film with 6 nm thickness is of the order of 106 Vcm-1 . These properties of the ultrathin SiO2 layer ensure its application in silicon quantum devices.