High-Quality CVD SiO2 Interfacial Layer Prepared by Cyclic Deposition with O2 Plasma Treatment

Abstract

We have developed a new process, cyclic deposition with plasma treatment (C-DOP), to obtain a high-quality interfacial layer (IL) that can be applied to low-temperature poly-Si thin-film transistors (TFTs). The C-DOP process uses sequential deposition followed by plasma treatment. By increasing radio frequency power during plasma treatment, the film becomes denser, and the density of the C-DOP-formed becomes close to that of thermal oxide. The amounts of residual impurities, such as , H, and C, are decreased by the C-DOP process. We applied the C-DOP process to form a thin IL. It is effective in suppressing the flatband voltage shift due to Fowler–Nordheim negative stress when the IL thickness is more than . By applying the C-DOP-formed IL to poly-Si TFTs, drain-current degradation due to drain-avalanche hot-carrier stress is successfully suppressed, and the time to 10% reduction of the drain current is prolonged by 1 order of magnitude.