Browsing by Author "Teng, Tun-Chien"

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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
Method of compensating for pixel migration in volume holographic optical disc (VHOD)
(2012-09-10)
Yu, Yeh-Wei
;
Cheng, Chih-Yuan
;
Teng, Tun-Chien
;
Chen, Cheng-Hsien
;
Lin, Shiuan-Huei
Volume holographic optical disc (VHOD) technology is simpler than the angular multiplexing holographic system. However, disc rotation usually causes pixel migration, thus reducing signal quality. This study proposes a special geometrical arrangement to counteract pixel migration. Using paraxial approximation analysis, an optimal geometrical distance ratio, K, is calculated to compensate for pixel migration and improve image quality during disc rotation. The results of approximation analysis are confirmed by both simulation and experimental results. (C) 2012 Optical Society of America