Effects of Excimer Laser Irradiation on the Characteristics of a-Si:H TFT's

Abstract

We have investigated the annealing effects of ultraviolet (UV) irradiation on the characteristics of hydrogenated amorphous silicon (a-Si:H) thin films and hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFT's) using XeCl excimer laser. The pulse duration of laser was 30nsec/shot and its intensity was varied from 10mJ/cm2 to 80 mJ/cm2. By irradiating the excimer laser on the a-Si:H TFT's degraded by the electrical stress and/or the visible light illumination, the characteristics of TFT's, such as the on- current, threshold voltage, field-effect mobility and subthreshold sharpness, have been effectively restored to those of virgin sample, while the leakage current changed little. It should be noted that the a-Si:H channel layer was not crystallized by varying the laser intensity.