Amorphous Titanium Oxide Semiconductors on Quasi-Crystal-Like InGaZnO Channels for Thin Film Transistor Applications

This paper reports an InGaZnO thin-film transistor with titanium-oxide semiconductor as channel capping layer. Based on the experimental results, the titanium-oxide semiconductor has the function of not only a surface passivation layer to reduce the defect states localized at grain boundaries near source/drain contacts, but also a mobility booster to enhance electric field across channel. Compared to control IGZO TFT, the crystalline IGZO TFTs with titanium-oxide semiconductor exhibits an improved performance of a low drive voltage of
${<}{\hbox{5 V}}$
, a low threshold voltage of 1.9 V, a low sub-threshold swing of 244 mV/decade , and a high mobility of 13.7 cm
$^{2}{\hbox{/V}}\cdot{\hbox{s}}$
. The simple titanium-oxide capping process have been demonstrated in this work, which provides considerable potential for further display applications requiring a low power operation and a low-temperature fabrication.