High-mobility thin-film transistor with amorphous InGaZnO4 channel fabricated by room temperature rf-magnetron sputtering

Thin-film transistors (TFTs) were fabricated using amorphous indium gallium zinc oxide (a-IGZO) channels by rf-magnetron sputtering at room temperature. The conductivity of the a-IGZO films was controlled from similar to 10(-3) to 10(-6) S cm(-1) by varying the mixing ratio of sputtering gases, O-2/(O-2+Ar), from similar to 3.1% to 3.7%. The top-gate-type TFTs operated in n-type enhancement mode with a field-effect mobility of 12 cm(2) V-1 s(-1), an on-off current ratio of similar to 10(8), and a subthreshold gate voltage swing of 0.2 V decade(-1). It is demonstrated that a-IGZO is an appropriate semiconductor material to produce high-mobility TFTs at low temperatures applicable to flexible substrates by a production-compatible means. (c) 2006 American Institute of Physics.