Reliability of amorphous InGaZnO TFTs with ITO local conducting buried layer for BEOL power transistors

Abstract

The device reliability of a-IGZOTFTs with ITO local conducting buried layer (LCBL) has been investigated under positive gate bias stress and hot carrier stress for the application as BEOL power transistors. The drive current of a-IGZO TFTs could be controlled by the modulation of ITO LCBL thickness and distance under source/drain electrode. The threshold voltage shifts, the drain current degradation, and breakdown voltage have been measured and discussed according to the different ITO LCBL thickness and distance. The devices with thick ITO and short ITO distance are desirable for a power device for High/Low type I/O bridges. The devices with thin ITO and long ITO distance are desirable for Low/High type I/O bridges. The breakdown voltages are decreased with the increase of ITO thickness.