Improved AMOLED with aligned poly-Si thin-film transistors by laser annealing and chemical solution treatments

Abstract

Abstract Low-temperature polycrystalline silicon (LTPS) thin-film transistors (TFT) were prepared for the active-matrix organic light-emitting displays (AMOLED). The excimer laser annealing (ELA) recrystallization technique was employed with a chemical solution treatment process to improve the TFT characteristic uniformity and the AMOLED display image quality. The characteristics of the poly-Si array thin films were influenced by XeCl ELA optic module design, TFT device channel direction, and laser irradiation overlap ratio. The ELA system module provided aligned poly-Si grain size of 0.3 μm by the homogenization lens design. The chemical solution treatment process included a dilute HF solution (DHF), ozone (O3) water, and buffer oxide etching solution (BOE). The PMOS TFT showed better field effect mobility of 87.6 cm2/V s, and the threshold voltage was −1.35 V. The off current (Ioff) was 1.25×10−11 A, and the on/off current ratio was 6.27×106. In addition, the image quality of the AMOLED display was highly improved using the 2T1C structure design without any compensation circuit.