Enhancement-mode thin film transistor using amorphous phosphorus-doped Indium–Zinc–Tin-Oxide channel layer

Abstract

In this research, we investigated optical properties of amorphous Phosphorus-doped Indium–Zinc–Tin-Oxide (a-IZTO:P) thin films and their feasibility as the channel layer for thin film transistors (TFTs). The a-IZTO:P TFT with bottom-gate top-contact structure was prepared on silicon substrates by radio frequency (RF) magnetron sputtering at room temperature. After annealing in air at 350 °C, the IZTO:P films kept amorphous and showed good optical transmittance of over 80% within the visible range. The a-IZTO:P TFT operated in enhancement-mode and exhibited promising electrical performance with saturation mobility (μSAT) of 34.6 cm2/V∙s, threshold voltage (VTH) of 0.8 V, subthreshold swing (SS) of 0.53 V/decade and on/off current ratio (ION/IOFF) of 4.88 × 108. In addition, the stability of a-IZTO:P TFTs was also investigated.