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http://dx.doi.org/10.7471/ikeee.2021.25.3.501

Effect of Gate Dielectrics on Electrical Characteristics of a-ITGZO Thin-Film Transistors  

Kong, Heesung (Dept. of Electrical Engineering, Korea University)
Cho, Kyoungah (Dept. of Electrical Engineering, Korea University)
Kim, Sangsig (Dept. of Electrical Engineering, Korea University)
Publication Information
Journal of IKEEE / v.25, no.3, 2021 , pp. 501-505 More about this Journal
Abstract
In this study, we fabricated amorphous indium-tin-gallium-zinc-oxide thin-film transistors (a-ITGZO TFTs) with gate dielectrics of HfO2 and the mixed layers of HfO2 and Al2O3, and investigated the effect of gate dielectric on electrical characteristics of a-ITGZO TFTs. When only HfO2 was used as the gate dielectric, the mobility and subthreshold swing (SS) were 32.3 cm2/Vs and 206 mV/dec. For the a-ITGZO TFTs with gate dielectric made of HfO2 and Al2O (2:1, 1:1), the mobilities and SS were 26.4 cm2/Vs (2:1), 16.8 cm2/Vs(1:1), 160 mV/dec (2:1) and 173 mV/dec (1:1). On the other hand, the hysteresis window shown in transfer curves of the a-ITGZO TFTs was lessened from 0.60 to 0.09 V by the increase of Al2O3 ratio in gate dielectric, indicating that the interface trap density between the gate dielectric and channel layer decreases due to Al2O3.
Keywords
a-ITGZO thin-film transistor; $HfO_2$; HfAlO; hysteresis; interface trap density;
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