The effect of tail state on the electrical and the optical properties in amorphous IGZO

In order to investigate the effect of tail state on the electrical and the optical properties in amorphous IGZO(a-IGZO), a-IGZO films were deposited at room temperature on fused silica substrats using pulsed laser deposition method. The laser pulse energy was used as the processing parameter. In-situ post annealing was carried out at 150°C right after the film deposition. The O₂ partial pressure during the deposition and the post annealing was fixed to 10m Torr. The carrier mobility of the a-IGZO films had a range from 2 to 18 cm² /Vs at carrier concentrations greater than 10¹⁸ cm^-3 . As the laser energy density increased, the Hall mobility increased. And post annealing improved the Hall mobility, as well. The optical property was examined using the ultraviolet-visible spectroscopy. The aIGZO films that have low Hall mobility exhibited stronger and broader absorption tails in >3.0 eV region. Post annealing reduced the intensity of the tail-like absorption. The absorption tail in a-IGZO films is an important factor which affects the electrical and the optical properties.