Remarkably High Hole Mobility Metal-Oxide Thin-Film Transistors

High performance p-type thin-film transistor (p-TFT) was realized by a simple process of reactive sputtering from a tin (Sn) target under oxygen ambient, where remarkably high field-effect mobility (μ(FE)) of 7.6 cm(2)/Vs, 140 mV/dec subthreshold slope, and 3 × 10(4) on-current/off-current were measured. In sharp contrast, the SnO formed by direct sputtering from a SnO target showed much degraded μ(FE), because of the limited low process temperature of SnO and sputtering damage. From the first principle quantum-mechanical calculation, the high hole μ(FE) of SnO p-TFT is due to its considerably unique merit of the small effective mass and single hole band without the heavy hole band. The high performance p-TFTs are the enabling technology for future ultra-low-power complementary-logic circuits on display and three-dimensional brain-mimicking integrated circuits.