Browsing by Author "Wu, Wen-Hao"

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Demonstrating 1 nm-oxide-equivalent-thickness La2O3 and HfO2 multi-layer composite oxides on In0.53Ga0.47As MOS capacitor
(2016-01-08)
Wu, Wen-Hao
;
Lin, Yueh-Chin
;
Hou, Tzu-Ching
;
Lin, Tai-Wei
;
Hsu, Hisang-Hua
The use of a high k composite dielectric composed of La2O3 and HfO2 layers as the gate dielectric for In0.53Ga0.47As MOS application is proposed. Two multi-layer structures of La2O3 (1 nm)/HfO2 (1 nm) and La2O3 (0.5 nm)/HfO2 (0.5 nm) were deposited and annealed at 450 and 500 degrees C for device performance comparison. X-ray photoelectron spectroscopy, TEM and C-V measurements were used for the interface analysis between the oxide and the semiconductor. Finally, a 1 nm equivalent-oxide-thickness dielectric with small hysteresis of 88 mV and D-it of 1.9 x 10(12) cm(-2) eV(-1) was achieved for six layers of an La2O3 (0.5 nm)/HfO2 (0.5 nm) composite oxide structure on an In0.53Ga0.47As MOS capacitor with a post-deposition annealing temperature of 450 degrees C.
Effects of layer sequence and postdeposition annealing temperature on performance of La2O3 and HfO2 multilayer composite oxides on In0.53Ga0.47As for MOS capacitor application
(2014-03-01)
Wu, Wen-Hao
;
Lin, Yueh-Chin
;
Chuang, Ting-Wei
;
Chen, Yu-Chen
;
Hou, Tzu-Ching
In this paper, we report on high-k composite oxides that are formed by depositing multiple layers of HfO2 and La2O3 on In0.53Ga0.47As for MOS device application. Both multilayer HfO2 (0.8 nm)/La2O3 (0.8 nm)/In0.53Ga0.47As and La2O3 (0.8 nm)/HfO2 (0.8 nm)/In0.53Ga0.47As MOS structures were investigated. The effects of oxide thickness and postdeposition annealing (PDA) temperature on the interface properties of the composite oxide MOS capacitors were studied. It was found that a low CET of 1.41 nm at 1 kHz was achieved using three-layer composite oxides. On the other hand, a small frequency dispersion of 2.8% and an excellent D-It of 7.0 Chi 10(11)cm(-2).eV(-1) can be achieved using multiple layers of La2O3 (0.8 nm) and HfO2 (0.8 nm) on the In0.53Ga0.47As MOS capacitor with optimum thermal treatment and layer thickness. (C) 2014 The Japan Society of Applied Physics
Improved linearity and reliability in GaN metal-oxide-semiconductor high-electron-mobility transistors using nanolaminate La2O3/SiO2 gate dielectric
(2016-04)
Hsu, Ching-Hsiang
;
Shih, Wang-Cheng
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Lin, Yueh-Chin
;
Hsu, Heng-Tung
;
Hsu, Hisang-Hua
Improved device performance to enable high-linearity power applications has been discussed in this study. We have compared the La2O3/SiO2 AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) with other La2O3-based (La2O3/HfO2, La2O3/CeO2 and single La2O3) MOS-HEMTs. It was found that forming lanthanum silicate films can not only improve the dielectric quality but also can improve the device characteristics. The improved gate insulation, reliability, and linearity of the 8 nm La2O3/SiO2 MOS-HEMT were demonstrated. (C) 2016 The Japan Society of Applied Physics
Improved linearity and reliability in GaN metal-oxide-semiconductor high-electron-mobility transistors using nanolaminate La2O3/SiO2 gate dielectric
(2016-04-01)
Hsu, Ching-Hsiang
;
Shih, Wang-Cheng
;
Lin, Yueh-Chin
;
Hsu, Heng-Tung
;
Hsu, Hisang-Hua
Improved device performance to enable high-linearity power applications has been discussed in this study. We have compared the La2O3/SiO2 AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) with other La2O3-based (La2O3/HfO2, La2O3/CeO2 and single La2O3) MOS-HEMTs. It was found that forming lanthanum silicate films can not only improve the dielectric quality but also can improve the device characteristics. The improved gate insulation, reliability, and linearity of the 8 nm La2O3/SiO2 MOS-HEMT were demonstrated. (C) 2016 The Japan Society of Applied Physics
Reliability improvement in GaN HEMT power device using a field plate approach
(2017-07-01)
Wu, Wen-Hao
;
Lin, Yueh-Chin
;
Chin, Ping-Chieh
;
Hsu, Chia-Chieh
;
Lee, Jin-Hwa
This study investigates the effect of implementing a field plate on a GaN high-electron-mobility transistor (HEMT) to improve power device reliability. The results indicate that the field plate structure reduces the peak electrical field and interface traps in the device, resulting in higher breakdown voltage, lower leakage current, smaller current collapse, and better threshold voltage control. Furthermore, after high voltage stress, steady dynamic on-resistance and gate capacitance degradation improvement were observed for the device with the field plate. This demonstrates that GaN device reliability can be improved by using the field plate approach. (C) 2017 Elsevier Ltd. All rights reserved.
Role of the cAMP-Dependent Carbon Catabolite Repression in Capsular Polysaccharide Biosynthesis in Klebsiella pneumoniae
(2013-02-11)
Lin, Ching-Ting
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Chen, Yu-Ching
;
Jinn, Tzyy-Rong
;
Wu, Chien-Chen
;
Hong, Yi-Ming
K. pneumoniae is the predominant pathogen isolated from liver abscesses of diabetic patients in Asian countries. Although elevated blood glucose levels cause various immune problems, its effects on K. pneumoniae virulence are unknown. This study investigated the regulation of capsular polysaccharide (CPS) biosynthesis, a major determinant for K. pneumoniae virulence, in response to exogenous glucose. We found that K. pneumoniae produce more CPS in glucose-rich medium via reduction in cyclic AMP (cAMP) levels. Individual deletion of cyaA or crp, which respectively encode adenylate cyclase and cAMP receptor protein in K. pneumoniae, markedly increased CPS production, while deletion of cpdA, which encodes cAMP phosphodiesterase, decreased CPS production. These results indicate that K. pneumoniae CPS biosynthesis is controlled by the cAMP-dependent carbon catabolite repression (CCR). To investigate the underlying mechanism, quantitative real-time PCR and promoter-reporter assays were used to verify that the transcription of CPS biosynthesis genes, which are organized into 3 transcription units (orf1-2, orf3-15, and orf16-17), were activated by the deletion of crp. Sequence analysis revealed putative CRP binding sites located on Porf3-15 and Porf16-17, suggesting direct CRP-cAMP regulation on the promoters. These results were then confirmed by electrophoretic mobility shift assay. In addition, we found putative CRP binding sites located in the promoter region of rcsA, which encodes a cps transcriptional activator, demonstrating a direct repression of CRP-cAMP and P-rcsA. The deletion of rcsA in mutation of crp partially reduced CPS biosynthesis and the transcription of orf1-2 but not of orf3-15 or orf16-17. These results suggest that RcsA participates in the CRP-cAMP regulation of orf1-2 transcription and influences CPS biosynthesis. Finally, the effect of glucose and CCR proteins on CPS biosynthesis also reflects bacterial resistance to serum killing. We here provide evidence that K. pneumoniae increases CPS biosynthesis for successful infection in response to exogenous glucose via cAMP-dependent CCR.
Use of Spin-On-Hard Mask Materials for nano scale patterning technology
(2008)
Wu, Wen-Hao
;
Chang, Edward Y.
;
Cheon, Hwan-Sung
;
Kim, Sang Kyun
;
Cho, Hyeon Mo
Amorphous Carbon Layer (ACL) and SiON system has been proven to be a good hardmask combination. These layers are formed by a high cost, low throughput CVD process. This paper discloses a reliable, low cost, high throughput process using a simple spin on layer structure. Through manipulation of various parameters, additional BARC layer is eliminated and the process is further simplified to a tri-layer structure. Also, PR/SiON/C-SOH (Carbon-Spin-On-Hardmask) system has been compared to PR / Si-SOH (Si-Spin-On-Hardmask) / C-SOH system and found their performances are comparable. This indicates the PR / Si-SOH / C-SOH process is an economical yet comparable substitute.