Schottky Contact-induced Hump Phenomenon by Bias and Optical Stresses in Amorphous Oxide Thin Film Transistor

Abstract

In this work, the hump characteristics induced by bias and light stresses are investigated through electrical measurements at various temperatures and TCAD simulations. To verify the origin of the hump current, transfer characteristics and source-to-drain currents with floated gate (S/D current) are measured at various temperatures. As a result, it is found that the source and drain (S/D) metals contacted with the active α-HIZO form the oppositely connected Schottky barrier diodes (SBD). Also, from the S/D current measurements after applying the stresses and TCAD simulations, it is revealed that the stress-induced enhancement of the S/D current can be understood that the trapped holes at the edge regions along the channel width direction make the Schottky barrier narrowing near the source-side edge regions and the hump occurs by the increase of the thermal generation and thermionic field emission current in the reverse-biased Schottky contact.