Browsing by Author "Hsu, Ching-Yi"

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Bias-Dependent Radio Frequency Performance for 40nm InAs High-Electron-Mobility Transistor with a Cutoff Frequency Higher than 600GHz
(2012-11-01)
Fatah, Faiz
;
Kuo, Chien-I
;
Hsu, Heng-Tung
;
Chiang, Che-Yang
;
Hsu, Ching-Yi
In this paper, we present the fabrication and characterization of 40 nm InAs-channel high-electron-mobility-transistor (HEMT) devices. Both DC and RF measurements were performed under various bias conditions. We have also extracted bias-dependent intrinsic device parameters to determine the optimum conditions of operation. It is concluded that a high current-gain cutoff frequency (f(T)) of 615 GHz can be achieved when the device is biased near the occurrence of impact ionization. (C) 2012 The Japan Society of Applied Physics
Development of Time-Multiplexed Backlight on Auto-stereoscopic LCD for Multi-user and Wide-viewing Angle Function
(2012-01-01)
Huang, Yi-Pai
;
Ting, Chih-Hung
;
Hsu, Ching-Yi
;
Yang, Che-Hsuan
;
光電工程學系
Current Time-Multiplexed backlight system can only produce a single user 3D display. Thus, a multi-user 3D film was proposed to add in front of the directional sequential backlight system and make the display for three users. Furthermore, a high resolution time-multiplexed backlight with tracking system for multi-user applicable wide-viewing auto-stereoscopic LCD was proposed. By utilizing an adjustable fine-stripe (AFS) backlight structure with a temporal switched 120Hz LCD, the 3D image could be displayed on high resolution, thus multi-user can observe wide-viewing 3D images at the same time.
Effect of Gate Length on Device Performances of AlSb/InAs High Electron Mobility Transistors Fabricated Using BCl3 Dry Etching
(2012-06-01)
Kuo, Chien-I
;
Hsu, Heng-Tung
;
Hsu, Ching-Yi
;
Yu, Chia-Hui
;
Ho, Han-Chieh
In this paper, we present the development of a mesa isolation process for AlSb/InAs high electron mobility transistors (HEMTs) using inductively coupled plasma (ICP) etching with BCl3 gas. Devices with different gate lengths (L-g: 60, 100, and 200 nm) fabricated by this dry etching technique show good DC and RF performances. With an appropriate L-g/gate-channel distance ratio, the 200-nm-gate has very high peak transconductances of 781 mS/mm at V-DS = 0.1 V and 2000 mS/mm at V-DS = 0.5 V. Moreover, an extrinsic current gain cutoff frequency of 137 GHz and maximum oscillation frequency of 97 GHz were achieved at a drain bias voltage V-DS = 0.3 V, indicating the great potential for such a device operating at high frequency with extremely low DC power consumption. (c) 2012 The Japan Society of Applied Physics
Enhancing ATP-based bacteria and biofilm detection by enzymatic pyrophosphate regeneration
(2010-04-15)
Lee, Hui-Ju
;
Ho, Ming-Rong
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Bhuwan, Manish
;
Hsu, Ching-Yi
;
Huang, Meng-Shun
The manufacturing processes of many electronic and medical products demand the use of high-quality water. Hence the water supply systems for these processes are required to be examined regularly for the presence of microorganisms and microbial biofilms. Among commonly used bacteria detection approaches, the ATP luminescence assay is a rapid, sensitive, and easy to perform method. The aim of this study is to investigate whether ATP regeneration from inorganic pyrophosphate, a product of the ATP luminescence assay, can stabilize the bioluminescence signals in ATP detection. ADPglc pyrophosphorylase (AGPPase), which catalyzes the synthesis of ATP from PP(i) in the presence of ADPglc, was selected because the system yields much lower luminescence background than the commercially available ATP sulfurylase/adenosine 5'-phosphosulfate (APS) system which was broadly used in pyrosequencing technology. The AGPPase-based assay could be used to measure both PPi and ATP quantitatively and shows 1.5- to 4.0-fold slight increases in a 10-min assay. The method could also be used to stabilize the luminescence signals in detection of Escherichia coli, Pseudo monas aeruginosa, and Bacillus cereus in either broth or biofilm. These findings suggest that the AGPPase-based ATP regeneration system will find many practical applications such as detection of bacterial biofilm in water pipelines. (C) 2009 Elsevier Inc. All rights reserved.
Exponential ATP amplification through simultaneous regeneration from AMP and pyrophosphate for luminescence detection of bacteria
(2011-11-01)
Lee, Hui-Ju
;
Ho, Min-Rong
;
Tseng, Chih-Sian
;
Hsu, Ching-Yi
;
Huang, Meng-Shun
Bacteria monitoring is essential for many industrial manufacturing processes, particularly those involving in food, biopharmaceuticals, and semiconductor production. Firefly luciferase ATP luminescence assay is a rapid and simple bacteria detection method. However, the detection limit of this assay for Escherichia cob is approximately 10(4) colony-forming units (CFU), which is insufficient for many applications. This study aims to improve the assay sensitivity by simultaneous conversion of PP(i) and AMP, two products of the luciferase reaction, back to ATP to form two chain-reaction loops. Because each consumed ATP continuously produces two new ATP molecules, this approach can achieve exponential amplification of ATP. Two consecutive enzyme reactions were employed to regenerate AMP into ATP: adenylate kinase converting AMP into ADP using UTP as the energy source, and acetate kinase catalyzing acetyl phosphate and ADP into ATP. The PP(i)-recycling loop was completed using ATP sulfurylase and adenosine 5' phosphosulfate. The modification maintains good quantification linearity in the ATP luminescence assay and greatly increases its bacteria detection sensitivity. This improved method can detect bacteria concentrations of fewer than 10 CFU. This exponential ATP amplification assay will benefit bacteria monitoring in public health and manufacturing processes that require high-quality water. (C) 2011 Elsevier Inc. All rights reserved.
Growth of ultrathin GaSb layer on GaAs using metal-organic chemical vapor deposition with Sb interfacial treatment
(2016-09)
Hsiao, Chih-Jen
;
Minh-Thien-Huu Ha
;
Hsu, Ching-Yi
;
Lin, Yueh-Chin
;
Chang, Sheng-Po
GaSb epitaxial layers were directly grown on GaAs substrates by metal-organic chemical vapor deposition involving Sb interfacial treatment with optimized growth temperature and V/III ratio. The interfacial treatment effectively reduces the surface energy and strain energy difference, resulting in a quasi-2D growth mode. When the GaSb layer was grown at 520 degrees C, the strain induced by lattice mismatch was accommodated by 90 degrees dislocations with a period of 5.67 nm. By optimizing the V/III ratio, the surface roughness of the ultrathin GaSb/GaAs heterostructure was reduced, resulting in a reduced carrier scattering and improved electronic properties. (C) 2016 The Japan Society of Applied Physics
Late-news student poster: Wide viewing angle 3D depth-fused display (DFD) system
(2008)
Hsu, Ching-Yi
;
Huang, Yi-Pai
;
Chang, Yu-Chen
;
Ding, Zhi-Hong
;
Su, Chih-Ping
Viewing angle caused by images shift is the most serious issue for depth-fused display (DFD). A wide viewing angle 3D-DFD system utilized high collimated backlight with wide viewing angle micro-lens array was proposed to avoid the images shift From the experiment results, the viewing angle was demonstrated to be increased to 0 = 30 degrees similar to +/- 40 degrees, which is much wider than that of conventional DFD (theta <+/- 10 degrees). Consequently. the proposed 3D-DFD system will be glasses-less, fatigue-less, and wide viewing.
Monolithic 3D CMOS Using Layered Semiconductors
(2016-04-06)
Sachid, Angada B.
;
Tosun, Mahmut
;
Desai, Sujay B.
;
Hsu, Ching-Yi
;
Lien, Der-Hsien
Monolithic 3D integrated circuits using transition metal dichalcogenide materials and low-temperature processing are reported. A variety of digital and analog circuits are implemented on two sequentially integrated layers of devices. Inverter circuit operation at an ultralow supply voltage of 150 mV is achieved, paving the way to high-density, ultralow-voltage, and ultralow-power applications.
Normally-OFF GaN MIS-HEMT With F- Doped Gate Insulator Using Standard Ion Implantation
(2018-01-01)
Wu, Chia-Hsun
;
Han, Ping-Cheng
;
Quang Ho Luc
;
Hsu, Ching-Yi
;
Hsieh, Ting-En
A normally-OFF GaN metal-insulator-gate high electron mobility transistors with fluorine doped gate insulator has been fabricated using standard ion implantation technique. Fluorine ions with negative charges were doped lightly into both the gate insulator and the partially recessed barrier layer, resulting in high positive threshold voltage (V-th) for the device, meanwhile preserving low ON-resistance. Compared to the fluorine-free and recess-free device, only about 16% increase of ON-resistance was observed for the F- doped devices. The fabricated F- doped device exhibits a threshold voltage of +0.68 V at I-Ds = 5 mu A/mm, a current density of 620 mA/mm, an OFF-state breakdown voltage of 800 V, and high ON/OFF current ratio of 10(10). For thermal stability consideration of fluorine dopant, the V-th-thermal stability test and positive bias temperature instability test were also discussed.
Novel depth-fused display (DFD) system with wide viewing 3D images
(2008)
Hsu, Ching-Yi
;
Huang, Yi-Pai
;
Chang, Yu-Chen
;
Su, Chih-Ping
;
光電工程學系
Viewing angle caused by images shift is the most serious issue for depth-fused display (DFD). A wide viewing angle 3D-DFD system utilized high collimated backlight with wide viewing angle micro-lens array was proposed to avoid the images shift. From the experiment results, the viewing angle was demonstrated to be increased to theta = +/-30 degrees similar to +/-40 degrees, which is much wider than that of conventional DFD (theta<+/-10 degrees). Consequently, the proposed 3D-DFD system will be glasses-less, fatigue-less, and wide viewing.
Study of Inherent Gate Coupling Nonuniformity of InAs/GaSb Vertical TFETs
(2016-11)
Hsu, Ching-Yi
;
Zeng, Yuping
;
Chang, Chen-Yen
;
Hu, Chenming
;
Chang, Edward Yi
An electrostatic nonuniformity in the cantilever vertical tunneling FETs intrinsically exists in the InAs/GaSb junction to InAs cantilever transition region. The effects of the coupling ratio (CR) nonuniformity are investigated in this paper. The results show that the switching characteristics are degraded by the CR nonuniformity, especially in the case of large InAs/GaSb band offset. This paper also reveals that the nonuniformity in InAs/GaSb vertical tunneling FETs can be mitigated with the optimized band offset of heterojunction, scaling of oxide thickness, and acute angle etching profile.
Suppressing Non-Uniform Tunneling in InAs/GaSb TFET With Dual-Metal Gate
(2016-03-01)
Hsu, Ching-Yi
;
Chang, Chun-Yen
;
Chang, Edward Yi
;
Hu, Chenming
;
材料科學與工程學系
Non-uniformity in electric field causes early onset of tunneling near the edge of InAs/GaSb hetero-junction tunneling field-effect transistors. When a small area, often an edge, of the tunneling junction has a lower turn-on voltage, the steep switching characteristic is degraded. Fermi pinning at InAs surface greatly worsen the uniformity. We propose a dual-metal gate structure to address the non-uniformity issue. With proper choice of work functions, the dual-metal gate structure can effectively suppress the early onset of edge tunneling and significantly improve the subthreshold swing.