SIO2 FORMATION BY THERMAL EVAPORATION OF SIO IN OXYGEN ATMOSPHERE USED TO FABRICATION OF HIGH-PERFORMANCE POLYCRYSTALLINE SILICON THIN-FILM TRANSISTORS

A reactive evaporation of SiO in an oxygen atmosphere was investigated for forming a good interface of SiO2/Si. SiO2 films are formed at room temperature by evaporation of a SiO powder in an oxygen atmosphere with a flow rate of 2 sccm at a pressure of 1X10(-4) Torr. The interface trapping density at SiO2/Si was lower than 5X10(10) cm-2 eV-1. n- and p-channel Al-gate polycrystalline silicon thin film transistors (poly-Si TFTs) were fabricated at 270-degrees-C with the present SiO2 films as a gate oxide and laser crystallized poly-Si films formed using a pulsed XeCl excimer laser. They showed good characteristics of a low threshold voltage of 1.1 V (n-channel) and -1.2 V (p-channel), and a high carrier mobility of 450 CM2/V s (n-channel) and 270 cm2/V s (p-channel).