Comparison of ZnO-Based JFET, MESFET, and MISFET

We compare key properties of zinc oxide (ZnO)-based junction field-effect transistors (JFETs), metal-semiconductor field-effect transistors (MESFETs), and metal-insulator-semiconductor field-effect transistors (MISFETs) prepared from a common ZnO: Mg thin film. The JFETs are fabricated with a ZnCo2O4-gate, the MESFETs with reactively sputtered Pt-gate and the MISFETs with WO3 as gate insulator. The three FET types are compared with regarding dc characteristics, frequency dependence, and stability at temperatures up to 150 degrees C. All devices can be switched within a similar gate voltage range of less than 3 V, making a direct comparison of the device characteristics possible. Measurements above room temperature show a common shift of the transfer curves to higher gate voltages, which seems to be a distinguishing property of ZnO compared with other semiconductors. All electric measurements show major differences between the devices, which can be attributed to the different gate structures.