Evaluation of Potential Distribution in Channel Region of Amorphous InGaZnO Thin Film Transistor by Bias Applied Hard X-ray Photoelectron Spectroscopy

Abstract

The potential distribution image in the channel plane of an amorphous InGaZnO₄ (a-IGZO) thin film transistor in the device operation was evaluated by bias applied hard X-ray photoelectron spectroscopy (HAXPES). We observed that the potential in the direction of channel length changed as a function of source-drain and⁄or gate voltage condition. In particular, in the case of the turn-on voltage condition (saturation regime), a high potential region in the a-IGZO channel was clearly observed. HAXPES under bias voltage was found to be very useful to evaluate the potential in the channel region during transistor operation.