Novel InGaZnO inverters utilizing film profile engineering

Abstract

In this study we cleverly employ the film profile engineering (FPE) concept to fabricate amorphous InGaZnO (a-IGZO) thin-film transistor (TFT)-based inverters with a resistor-or transistor-load. In the fabrication the profiles of major thin films in both load and drive devices can be properly tailored with designed channel dimensions and deposition conditions. Although the inverter with a resistor-load is simpler in structure and fabrication, the switching performance is found to be restricted by the passive load component. The performance can be greatly promoted as a depletion-mode transistor-load is used instead. Full-swing operation is demonstrated for the inverter with a voltage gain of 28 recorded at an operation voltage (V-DD) of 5V. (C) 2015 The Japan Society of Applied Physics