Solution-processed amorphous gallium oxide gate dielectric for low-voltage operation oxide thin film transistors

Abstract

Here, gallium oxide (Ga2O3) thin films were investigated as gate dielectric for thin-film transistors (TFTs) using the solution process method. The optical, microstructure, morphology, oxygen vacancy defect states and electrical performance metrics of Ga2O3 thin films annealed at different stages of temperature were explored. The excellent dielectric property of amorphous Ga2O3 thin films was found, but it was deteriorated after crystallization when the annealing temperature increased. The optimized Ga2O3 thin film exhibits a low leakage current density of 1.9 × 10–6 A cm−2 at 1.5 MV cm−2 and a large dielectric constant of 10.8. Furthermore, low-voltage operation oxide TFTs were demonstrated using this optimized amorphous Ga2O3 as gate dielectric. The device exhibits excellent bias stress stability with a high mobility of 8.5 cm2/Vs, a threshold voltage of -1.4 V, a current on/off ratio of 104 and a subthreshold swing of 0.41 mV/Dec.