Laser Treatment of Zinc Tin Oxide used as Active Layer in a Metal Oxide Semiconductor Thin Film Transistor

Laser treatment of solution processed zinc tin oxide (ZTO) thin film for its application as the active layer in a metal oxide semiconductor thin film transistor (MOS-TFT) is being reported. A conventional approach to improve the device performance of ZTO TFTs consists in annealing the active layer at high temperatures (above 500^oC) with an oven. Such an approach is not applicable to temperature-sensitive device, though. On the other hand, laser annealing has the advantage of high energy, fast speed, controllable treatment area, and less damage to substrate compared to oven annealing. In this study, a nanosecond laser capable of operating at fixed wavelengths and fluences is used to irradiate ZTO films. Structural properties and surface topology of the laser-irradiated ZTO films are evaluated using x-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. These properties, along with device performance, are of focus in comparing ZTO TFTs with different annealing treatments.