Polycrystalline In-Ga-O semiconductor for high-performance thin-film transistor

We have developed a high mobility oxide semiconductor using a polycrystalline In-Ga-O (IGO) as a channel material. The IGO thin-film transistor (TFT) showed a field-effect mobility of 39.1 cm²V^-1 s^-1, a threshold voltage of 1.4 V, and a subthreshold gate voltage swing of 0.12 V/decade. The polycrystalline IGO thin film showed the cubic bixbyite structure of In₂O₃ without an obvious preferred orientation. The average grain size of polycrystalline IGO was about 10 μm. The high mobility of IGO TFT is related to the In₂O₃ crystalline phase and large grain size of the IGO film. The potential barrier height at grain boundary of the polycrystalline IGO was lower than 20 meV.