The Effects of UV Exposure on Plasma-Enhanced Atomic Layer Deposition ZnO Thin Film Transistor

Abstract

We investigated the effects of UV treatment on the device properties of a plasma-enhanced atomic layer deposition (PE-ALD) ZnO thin film transistor (TFT). Remote PE-ALD ZnO thin films were used as active layers for bottom-gate TFT devices. The as-deposited PE-ALD ZnO film at a growth temperature of 200?? C has an overly small carrier concentration, which produces a TFT device with no modulation by gate voltage sweep. However, after UV light exposure, the device shows proper TFT modulation by gate voltage. The threshold voltage (Vth) of the device can be controlled to the negative direction by increasing the UV exposure time. Vth moves from 17.8 to -6.5 V with an increase in UV exposure time from 3 to 120 min. ?? 2010 The Electrochemical Society.