Highly reliable liquid-phase-deposited SiO2 with nitrous oxide plasma post-treatment for low-temperature-processed polysilicon thin film transistors

Abstract

Low-temperature ( similar to 300 C) N2O-plasma post-treatment for liquid-phase-deposited (LPD) gate oxide has been proposed for the first time. This treatment successfully takes the place of conventional furnace annealing in O-2 ambient. Results of physicochemical and electrical characteristics shock that N2O-plasma post-treated LPD-SiO2 has a high electrical breakdown field and low interface State density. In addition. N2O-plasma treatment also improves the Si-rich phenomenon of LPD-SiO2. From the comparison with pure N2O-plasma oxidation film, LPD-SiO2 with its short re-oxidation time in N2O plasma plays an important role in relieving interfacial stress. Finally, the novel technology is applied to the gate oxide of low-temperature-processed (LTP) polysilicon thin film transistors (poly-Si TFTs). The device performance reveals excellent electrical characteristics, and the reliability shows a satisfactory result. as well as the gate oxide reliability. It is believed that the N2O-plasma post-treatment not only improves the oxide quality, but also effectively passivates the trap states of poly-Si TFTs.