Performance enhancement of solution-processed amorphous WZTO TFT with HAO gate dielectric via power ultrasound technology

Abstract

In this paper, power ultrasound technology (PUT) is employed to prepare the high-k hafnium-aluminum oxide (HAO) dielectric and thin film transistor (TFT). The continuous propagation of high-intensity ultrasonic waves in the metal oxide precursor solution can improve the dissolution efficiency of the solute and speed up the formation of the HAO precursor solution. The prepared HAO films have a smooth surface roughness of 0.36 nm and high optical transmittance of 85 %. Moreover, HAO films obtain excellent electrical properties with a relative permittivity of 15.9 and a leakage current density of 9.1 × 10−8 A/cm2 at 2 MV/cm as well. Finally, we successfully fabricate TFT with HAO dielectric using PUT, these TFTs exhibit switch characteristics with field effect mobility of 18.7 cm2v−1s−1, threshold voltage (Vth) of −0.47 V, and Vth shift of 0.35 V under positive gate bias stress. The results show that the PUT is a promising method that can remarkably decrease the preparation time of the precursor solution and improve the TFT performance.