High Performances of Low Temperature (≤ 600°C) Unhydrogenated Polysilicon Thin Film Transistors

Abstract

AbstractLow temperature unhydrogenated polysilicon thin film transistors are elaborated through a fourmask gate aluminium process. Temperature process does not exceed 600°C. Active layer is made of undoped polysilicon layer, an in-situ phosphorus polysilicon layer constitutes source and drain windows and a SiO2 APCVD layer ensures gate insulation. The transistors exhibit electrical properties as good as in the case of hydrogenated ones: a low threshold voltage (VT = 4–5 V), an acceptable optimum field effect mobility (≅ 42 cm2/Vs), a high On/Off state switching, and a high On/Off state current ratio (≅ 107) for a drain voltage equal to 1 V.