Browsing by Author "Cheng, Chin-Pao"

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Crystallized Ohmic Contact Effect in AlGaN/GaN High Electron Mobility Transistor
(2013-08-01)
Liao, Sheng Yu
;
Chang, Tsu
;
Hsu, Hsiao-Hsuan
;
Cheng, Chun-Hu
;
Chang, Liann-Be
In this study, we investigate the grain size effect of high electron mobility transistor devices with ohmic contact metals of stacked Ti/Al/Ni/Au and Ti/Al/Mo/Au. In addition to a comparison of electrical characteristics, the ohmic contacts were also examined by a scratch test for the observation of adhesion behavior. The experimental results demonstrate that the metal grain size is strongly dependent on metal adhesion, which may lead to bonding issues. Moreover, the grain-induced lateral stress lowers the drive current and increases the off-state current owing to the degraded gate swing and transconductance of transistor switching characteristics. (C) 2013 The Japan Society of Applied Physics
High Mobility Field-Effect Thin Film Transistor Using Room-Temperature High-kappa Gate Dielectrics
(2014-10-01)
Hsu, Hsiao-Hsuan
;
Chang, Chun-Yen
;
Cheng, Chun-Hu
;
Chen, Po-Chun
;
Chiu, Yu-Chien
This paper reports an InGaZnO thin-film transistor (TFT) that involves using fully room-temperature gate dielectrics on a flexible substrate. The wide bandgap dielectrics of HfO2 and Y2O3 exhibited favorable adhesion properties on a flexible substrate compared with conventional low-kappa SiO2 film. Based on the experimental results, the room-temperature IGZO/HfO TFTs demonstrated effective device integrity, and achieve a low drive voltage of < 2 V, a low threshold voltage of 0.46 +/- 006 V, a low sub-threshold swing of 110 +/- 6 mV/decade and an extremely high mobility of 60.2 +/- 32 cm(2)/V s. The excellent performance of this TFT indicated that it demonstrates considerable potential for active-matrix liquid crystal display applications requiring low power consumption and a high driving current.
Structural stability of diffusion barriers in thermoelectric SbTe: From first-principles calculations to experimental results
(2014-03-05)
Hsu, Hsiao-Hsuan
;
Cheng, Chun-Hu
;
Chiou, Shan-Haw
;
Huang, Chiung-Hui
;
Liu, Chia-Mei
This study involved developing robust diffusion barrier for n-type antimony telluride (SbTe) thermoelectric devices. Compared to conventional Ni barrier, the mid-band metals of Ta and TaN with favored ohmic-like contact exhibited smaller diffusion tail because of structurally stable interface on SbTe, which have been supported by first-principles calculations and demonstrated by experimental results. Furthermore, the TaN barrier has strong ionic Ta-N bonding and a high total energy of -4.7 eV/atom that could effectively suppress the formation of SbTe-compounds interfacial layer. (C) 2013 Elsevier B. V. All rights reserved.