Improvement in Field-Effect Mobility of Indium Zinc Oxide Transistor by Titanium Metal Reaction Method

This paper examined the effects of postdeposition annealing on the electrical properties of titanium-capped (TC) indium–zinc oxide (IZO) films and their IZO thin-film transistors. The TC IZO transistor oxidized at the temperature of 300 °C exhibited a high field-effect mobility of 61.0 cm
$^{2}$
/Vs, low subthreshold gate swing of 110 mV/decade,
$V_{\rm th}$
of −0.4 V, and high
$I_{{\mathrm{{\scriptscriptstyle ON}}/\mathrm{{\scriptscriptstyle OFF}}}}$
ratio of
$2.3 \times 10^{8}$
. In addition, the positive gate bias stress-induced stability of the TC IZO transistor was better than that of the control device without metal capping treatment. This was attributed to the scavenging effect of the loosely bonded oxygen species in the IZO semiconductor by titanium thermal oxidation.