Full-Swing, High-Gain Inverters Based on ZnSnO JFETs and MESFETs

Metal-semiconductor and junction n-channel field-effect transistors (MESFETs and JFETs) have been fabricated on glass substrates using room temperature deposited amorphous zinc-tin oxide (ZTO) channel layers. Characteristics of transistors and inverter circuits are compared. Best FET devices exhibit ON-to- OFF current ratios over eight orders of magnitude, subthreshold swings as low as 250 mV/dec and field-effect mobilities of 5 cm ² /Vs. Furthermore, all devices show long-term stability over a period of more than 200 days. Inverters fabricated using either MESFETs or JFETs exhibit remarkable peak gain magnitude values of 350 and voltage uncertainty levels as low as 260 mV for an operating voltage of 5 V. A Schottky diode FET logic (SDFL) approach is applied to shift the switching voltage which is a requirement for cascading of inverters for realization of ring oscillators.