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Dielectric and physical properties of N2O-oxynitrided (RTON) ultrathin (5-10 nm) SiO2 films formed by in situ multiple rapid thermal processing have been investigated. In high-field stressing under positive and negative polarity biases, the RTON SiO2 films showed a much lower electron-trap generation rate, a lower field-induced leakage current and a higher charge-to-breakdown value, as compared to those of pure SiO2 and rapid thermally NH3-nitrided (RTN) SiO2 films. Fourier transform-infrared reflection attenuated total reflectance (FT-IR ATR) and X-ray photoelectron spectroscopy (XPS) results showed that strong Si-N bonds are formed at the SiO2/Si interface by RTON, whereas a large number of N-H and Si-H bonds, which act as electron traps, are also generated by RTN.

Formation of 5-nm-thick SiO2 film has been studied by rapid thermal processing (RTP). The SiO2/Si(100) interface of 5-nm RTP-grown SiO2 film evaluated by high-resolution TEM is quite uniform, at least ordered within one or two atomic layers. The TDDB characteristics have indicated that short-time breakdown failure diminishes with decreasing oxide thickness, drastically below 6 nm in thickness. However, leakage current at low field, which is related to oxide wear-out, is observed in ultrathin RTP-SiO2 film (2 as a gate oxide of MOSFETs and obtained sufficient subthreshold and transconductance characteristics as device performance.