The effects of composition of a-SiGe channel layer and annealing temperature on the electrical performances of the inverted-staggered thin-film transistors with Sb/Al binary alloy Schottky source/drain contact had been studied. The experimental results indicated that the device effective electron mobility could be enhanced significantly by reducing the Schottky barrier height between the source/drain contact metal and a-SiGe:H channel layer, and using an appropriate annealing temperature. Furthermore, by employing a composition-graded a-SiGe channel layer to form the source/drain Schottky contact with the top a-Ge:H channel segment, the device effective electron mobility could be further improved.