Schottky barrier source-gated ZnO thin film transistors by low temperature atomic layer deposition

Abstract

We have fabricated ZnO source-gated thin film transistors (SGTFTs) with a buried TiW source Schottky barrier and a top gate contact. The ZnO active channel and thin high-κ HfO2 dielectric utilized are both grown by atomic layer deposition at temperatures less than 130 °C, and their material and electronic properties are characterized. These SGTFTs demonstrate enhancement-mode operation with a threshold voltage of 0.91 V, electron mobility of 3.9 cm2 V−1 s−1, and low subthreshold swing of 192 mV/decade. The devices also exhibit a unique combination of high breakdown voltages (>20 V) with low output conductances.