DC sputter deposition of amorphous indium-gallium-zinc-oxide (a-IGZO) films with H2O introduction

Amorphous indium-gallium-zinc-oxide (a-IGZO) films were deposited by dc magnetron sputtering with H2O introduction and how the H2O partial pressure (PH2O) during the deposition affects the electrical properties of the films was investigated in detail. Resistivity of the a-IGZO films increased dramatically to over 2 x 105 Ωcm with increasing PH2O to 2.7 x 10-2 Pa while the hydrogen concentration in the films increased to 2.0 x 1021 cm-3. TFTs using a-IGZO channels deposited under PH2O at 1.6-8.6 x 10-2 Pa exhibited a field-effect mobility of 1.4-3.0 cm2/Vs, subthreshold swing of 1.0-1.6 V/decade and on-off current ratio of 3.9 x 107-1.0 x 108.