Oxygen plasma and high pressure H2O vapor heat treatments used to fabricate polycrystalline silicon thin film transistors
Oxygen plasma and high pressure H2O vapor heat treatment were applied to fabrication of n-channel polycrystalline silicon thin film transistors (poly-Si TFTs). 13.56 MHz-oxygen-plasma treatment at 250 °C, 100 W for 5 min effectively reduced defect states of 25-nm-thick silicon films crystallized by 30 ns-pulsed XeCl excimer laser irradiation. 1.3×106-Pa-H2O vapor heat treatment at 260 °C for 3 h was carried out in order to improve electrical properties of SiOx gate insulators and SiOx/Si interfaces. A carrier mobility of 470 cm2/Vs and a low threshold voltage of 1.8 V were achieved for TFTs fabricated with crystallization at 285 mJ/cm2.