Effects of Oxide Thickness and Oxidation Parameters on the Electrical Characteristics of Thin Oxides Grown by Rapid Thermal Oxidation of Si in N20

The electrical properties of oxide layers grown on Si in N20 ambient were found a function of oxide growth tempera-ture and oxide thickness. In general, the properties of the oxide were improved when the oxide growth temperature was i 150 ~ and higher. The parameters of interest were oxide fixed charge density, leakage current, and stress induced degra-dation. The degradation in i0 nm oxide was found less compared with that in 7 nm oxide. The formation of more silicon-nitrogen bonds at higher growth temperature and subsequent reduction in silicon-oxygen bonds were used to explain the observations. The continuous decrease of device dimensions in MOS VLS I and ULS I circuits requires highly reliable ultrathin (<10 nm) gate oxide layer for the MOS transistors. These layers should be: (i) resistant to radiation, (it) resistant to hot carriers, and (iii) capable of blocking impurity penetra-tion into SiO2. Also these layers must have high breakdown electric field and low interface and bulk trap density. It has been shown that thin oxide layers grown by rapid therma