Browsing by Author "Chiu, Yu Sheng"

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Electrical Characteristics of Al2O3/InSb MOSCAPs and the Effect of Postdeposition Annealing Temperatures
(2013-05-01)
Hai Dang Trinh
;
Lin, Yueh Chin
;
Chang, Edward Yi
;
Lee, Ching-Ting
;
Wang, Shin-Yuan
The characteristics of Al2O3/InSb MOSCAPs processed with different postdeposition annealing (PDA) temperatures are investigated. X-ray photoelectron spectroscopy analysis shows a significant reduction of InSb-oxides after HCl plus trimethyl aluminum treatment and oxide deposition. Multifrequency capacitance-voltage (C-V) characteristics exhibit low-frequency and asymmetrical C-V behaviors, in which capacitance in the InSb conduction band side is lower than in the valence band side. The electrical properties of the MOSCAPs are sensitive to PDA temperature and degraded significantly at PDA temperature > 300 degrees C. This degradation is closely related to the diffusion of In, Sb into Al2O3 as indicated by transmission electron microscopy analyses.
Evaluation of AlGaN/GaN metal-oxide-semicondutor high-electron mobility transistors with plasma-enhanced atomic layer deposition HfO2/AlN date dielectric for RF power applications
(2017-09-01)
Chiu, Yu Sheng
;
Luc, Quang Ho
;
Lin, Yueh Chin
;
Huang, Jui Chien
;
Dee, Chang Fu
A plasma enhanced atomic layer deposition (PEALD) HfO2/AlN dielectric stack was used as the gate dielectric for AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) for high-frequency power device applications. The capacitance-voltage (C-V) curves of the HfO2/AlN/GaN MOS capacitor (MOSCAP) showed a small frequency dispersion along with a very small hysteresis (similar to 50 mV). Moreover, the interface trap density (D-it) was calculated to be 2.7 x 10(11)cm(-1)V(-1) s(-1) at 150 degrees C. Using PEALD-AlN as the interfacial passivation layer (IPL), the drain current of the HfO2/AlN MOS-HEMTs increased by about 46% and the gate leakage current decreased by six orders of magnitude as compared with those of the conventional Schottky gate AlGaN/GaN HEMTs processed using the same epitaxial wafer. The 0.3-mu m-gate-length HfO2/AlN/AlGaN/GaN MOS-HEMTs demonstrated a 2.88W/mm output power, a 23 dB power gain, a 30.2% power-added efficiency at 2.4 GHz, and an improved device linearity as compared with the conventional AlGaN/GaN HEMTs. The third-order intercept point at the output (OIP3) of the MOS-HEMTs was 28.4 as compared with that of 26.5 for the conventional GaN HEMTs. Overall, the MOS-HEMTs with a HfO2/AlN gate stack showed good potential for high-linearity RF power device applications. (C) 2017 The Japan Society of Applied Physics
High-permitivity cerium oxide prepared by molecular beam deposition as gate dielectric and passivation layer and applied to AlGaN/GaN power high electron mobility transistor devices
(2016-05)
Chiu, Yu Sheng
;
Liao, Jen Ting
;
Lin, Yueh Chin
;
Liu, Shin Chien
;
Lin, Tai Ming
High-kappa cerium oxide (CeO2) was applied to AlGaN/GaN high-electron-mobility transistors (HEMTs) as a gate insulator and a passivation layer by molecular beam deposition (MBD) for high-power applications. From capacitance-voltage (C-V) measurement results, the dielectric constant of the CeO2 film was 25.2. The C-V curves showed clear accumulation and depletion behaviors with a small hysteresis (20 mV). Moreover, the interface trap density (D-it) was calculated to be 5.5 x 10(11) eV(-1)cm(-2) at 150 degrees C. A CeO2 MOS-HEMT was fabricated and demonstrated a low subthreshold swing (SS) of 87 mV/decade, a high ON/OFF drain current ratio (I-ON/I-OFF) of 1.14 X 10(9), and a low gate leakage current density (J(leakage)) of 2.85 X 10(-9)Acm(-2) with an improved dynamic ON-resistance (R-ON), which is about one order of magnitude lower than that of a conventional HEMT. (C) 2016 The Japan Society of Applied Physics