Low-Temperature Process Compatibility for the Oxide Thin Film Transistors Using In-Ga-Zn-O Active Channels Prepared by Atomic-Layer Deposition at 150°C

We investigated the effects of post-annealing process temperature on the device characteristics and stabilities of the oxide thin-film transistors (TFTs) using the In-Ga-Zn-O (IGZO) active layers prepared by atomic-layer deposition process. The fabricated IGZO TFTs exhibited a high saturation mobility of 12.0 cm2/Vs and a subthreshold swing of 0.20 V/dec after the annealing at 150 °C. The density of tail and deep states for the ALD-IGZO TFTs annealed at 150 °C was estimated to be 7.3×1017 in the mid-gap region. The threshold voltage shifts for the TFTs annealed at 150 °C were estimated to be −3.5 and −2.3 V under the positive and negative bias temperature stress tests at 60 °C for 104 s, respectively.