SiOx interlayer to enhance the performance of InGaZnO-TFT with AlOx gate insulator

We have fabricated indium–gallium–zinc (IGZO) thin film transistor (TFT) using SiO x interlayer modified aluminum oxide (AlO x ) film as the gate insulator and investigated their electrical characteristics and bias voltage stress. Compared with IGZO-TFT with AlO x insulator, IGZO-TFT with AlO x /SiO x insulator shows superior performance and better bias stability. The saturation mobility increases from 5.6 cm 2 /V s to 7.8 cm 2 /V s, the threshold voltage downshifts from 9.5 V to 3.3 V, and the contact resistance reduces from 132 Ωcm to 91 Ωcm. The performance improvement is attributed to the following reasons: (1) the introduction of SiO x interlayer improves the insulator surface properties and leads to the high quality IGZO film and low trap density of IGZO/insulator interface. (2) The better interface between the channel and S/D electrodes is favorable to reduce the contact resistance of IGZO-TFT.