Browsing by Author "Chang, Edward-Yi"

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A Cu-Metallized InGaP/GaAs Heterojunction Bipolar Transistor with Reliable Pd/Ge/Cu Ohmic Contact for Power Applications
(2010)
Huang, Jui-Chien
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Lin, Yueh-Chin
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Tseng, Yu-Ling
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Chen, Ke-Shian
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Lu, Po-Chin
A Cu-metallized InGaP/GaAs heterojunction bipolar transistor (HBT) using a Pd/Ge/Cu n-type ohmic contact, a Pt/Ti/Pt/Cu p-type ohmic contact, and a Ti/Pt/Cu interconnect has been fabricated for power applications. The 4 x 20 mu m(2) HBT had an output power of 11.25 dBm with a power-added efficiency of 35.1%. After applying current-accelerated stress for 24 h, the current gain remained larger than 125. The device was also annealed at 200 degrees C for 24 h, and showed a slight decrease in output power from 10.06 to 9.83 dBm. The results demonstrated that reliable Cu metallization can be used for fabricating InGaP/GaAs HBTs for power applications. (C) 2010 The Japan Society of Applied Physics
Analysis of Leakage Current Mechanism for Ni/Au Schottky Contact on InAlGaN/GaN HEMT
(2018-06-06)
Lumbantoruan, Franky
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Wu, Chia-Hsun
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Zheng, Xia-Xi
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Singh, Sankalp K.
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Dee, Chang-Fu
The gate leakage mechanism for InAlGaN/GaN high electron mobility transistors (HEMTs) is systematically studied using temperature-dependent gate current-voltage characteristics. The electric field across the barrier layer is calculated through the extracted polarization charge and dielectric constant of the InAlGaN/GaN HEMT. The gate current of the InAlGaN/GaN HEMT is analyzed by fitting the experimental data using Themionic Emission (TE), Poole-Frenkel (PF), and Fowler-Nordheim (FN) tunneling. The results show that 1) reverse leakage current in the thin InAlGaN barrier layer is dominated by FN tunneling due to triangular barrier formation; 2) for thicker barrier layer, the reverse leakage current at low electric field (<2.23MVcm(-1)) is dominated by PF emission; 3) at high electric field near the threshold voltage the FN tunneling dominates. Extraction of effective barrier height by fitting the experimental data with models leads to the suggestion for the improvement of the device leakage current.
BUFFER-OPTIMIZED IMPROVEMENT IN RF LOSS OF ALGAN/GAN HEMTS ON 4-INCH SILICON (111)
(2017-01-01)
Luong, Tien Tung
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Lumbantoruan, Franky
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Chen, Yen-Yu
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Ho, Yen-Teng
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Lin, Yueh-Chin
The effect of different buffer layers on the RF losses of GaN-based high-mobility-transistors (HEMTs) on Si substrate has been studied. It is found that the electron inversion layer induced by the residual tensile stress in AlN buffer is responsible for a dominant loss factor. It is first time such mechanisms of the RF loss of GaN/Si is discussed. It is proven that using a thin high-low-high temperature (HLH) AlN buffer reducing the tensile stress in AlN consequently reduces the RF loss.
Characterization of Al2O3/ZnO Grown on Si Substrate by Plasma Enhanced Atomic Layer Deposition
(2013-01-01)
Chung, Chen-Chen
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Tran, Binh-Tinh
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Lin, Kung-Liang
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Wang, Ching-Chiun
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Chen, Chien-Chih
Characterization of nanolaminate Al2O3/ZnO oxide films grown on Si substrates was conducted by using plasma enhanced atomic layer deposition (PE-ALD) method. PE-ALD can minimize the structural imperfections in films and reduce substrate damage. The film deposition by using PE-ALD are dense, defect-free, highly uniform, conformal films and show excellent step coverage. Moreover, compared to other deposition techniques, it is possible to deposit high quality films at much lower temperatures. High resolution transmission electron microscope (TEM) images showed the existence of sharp interfacial layers among the Al2O3, ZnO layer, and the Si substrate for the growth rate of 1.56 angstrom/cycle, and the surface roughness of about 0.2 nm. The nanolaminate-stacking layer can be used in organic light emitting diode encapsulation application as the gas barrier.
Characterization of AlInN Layer Grown on GaN/Sapphire Substrate by MOCVD
(2013-02-01)
Huang, Wei-Ching
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Chang, Edward-Yi
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Wong, Yuen-Yee
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Lin, Kung-Liang
;
Hsiao, Yu-Lin
The AlInN layers have been grown with different growth parameters on GaN/sapphire substrates by metal-organic chemical vapor deposition (MOCVD). The effects of growth parameters such as pressure and temperature on the Al incorporation during AlInN material growth have been investigated. The results showed that lower pressure provides a tendency for higher Al incorporating in the AlInN layer. Besides, as the temperature was increased from 700 degrees C to 780 degrees C, an estimation of 4% reduction on the indium composition has been observed for each 20 degrees C increment. XRD analysis showed that the best crystal quality of AlInN occured at 80% Al composition because of the higher lattice matching with GaN. Based on the above criteria, an Al0.8In0.2N/GaN HEMT device with 2 mu m gate length has also been fabricated. The DC characteristics showed a saturated current, I-dss of 280 mA/mm and transconductance of 140 mS/mm.
Double delta-doped enhancement-mode InGaP/AlGaAs/InGaAs pseudomorphic high electron mobility transistor for linearity application
(2006-09-01)
Chu, Li-Hsin
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Hsu, Heng-Tung
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Chang, Edward-Yi
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Lee, Tser-Lung
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Chen, Sze-Hung
A high linearity and high efficiency enhancement-mode InGaP/AlGaAs/InGaAs pseudomorphic high electron mobility transistor (PHEMT) for single supply operation has been developed. The low voltage operation is achieved by the very low knee voltage of the device and the linearity is improved by the optimizing concentrations of the two 3 delta-doped layers. Biased at drain-to-source voltage V-DS = 2V, the fabricated 0.5 x 200 mu m(2) device exhibited a maximum transconductance of 448 mS/mm. The measured minimum noise figure (NFmin) was 0.86 dB with 12.21 dB associated gain at 10 GHz. The device shows a high output third-order intercept point (OIP3)-P-1dB of 13.2 dB and a high power efficiency of 35% when under wideband code-division multiple-access (W-CDMA) modulation signal.
Effect of Graded AlxGa1-xN Interlayer Buffer on the Strain of GaN Grown on Si (111) Using MOCVD Method
(2008)
Lin, KungLiang
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Chang, Edward-Yi
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Li, Tingkai
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Huang, Wei-Ching
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Hsiao, Yu-Lin
GaN film grown on Si substrate with AlN/AlxGa1-xN buffer is studied by low pressure metal organic chemical vapor deposition (MOCVD) method. The AlxGa1-xN film with Al composition varying from 0 similar to 0.66 was used. The correlation of the Al composition in the AlxGa1-xN film with the stress of the GaN film grown was studied using high resolution X-ray diffraction including symmetrical and asymmetrical omega/2 theta scans and reciprocal space maps. It is found that with proper design of the Al composition in the AlxGa1-xN buffer layer, crack-free GaN films can be successfully grown on Si (111) substrates using AlN and AlxGa1-xN buffer layers.
Effect of Low Temperature Ge Seed Layer and Post Thermal Annealing on Quality of Ge1-xSix (0.05 <= x <= 0.1) Graded Buffer Layers by UHV-CVD
(2014-07-01)
Chi-Lang Nguyen
;
Nguyen Hong Quan
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Binh-Tinh Tran
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Su, Yung-Hsuan
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Tang, Shih-Hsuan
High crystal quality, smooth surface and fully relaxed Ge1-xSix (0.05 <= x <= 0.1) buffers are grown on 6 degrees-off (100) Si substrate by UHV-CVD. A low-temperature (LT) Ge seed layer is used to improve the quality of the Ge1-xSix buffers. In this study, the LT-Ge seed layer is deposited directly onto the Si substrate at a low temperature of 315 degrees C. After that, stress-free Si0.1Ge0.9 and Si0.05Ge0.95 layers are grown, respectively. An in-situ annealing process is also performed for the Si0.1Ge0.9/LT-Ge layers to increase the degree of relaxation. The total thickness of the epitaxial layer is 270 nm, with the average surface roughness at 0.6 nm.
Effects of Al(x)Ga(1-x)N interlayer for GaN epilayer grown on Si substrate by metal-organic chemical-vapor deposition
(2010-05-01)
Lin, Kung-Liang
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Chang, Edward-Yi
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Hsiao, Yu-Lin
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Huang, Wei-Ching
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Luong, Tien-Tung
GaN film grown on Si substrate using multilayer AlN/Al(x)Ga(1-x)N buffer is studied by the low-pressure metal-organic chemical-vapor deposition method. The Al(x)Ga(1-x)N films with Al composition varying from 1 to 0.66 were used to accommodate the stress induced between GaN and the Si substrate during GaN growth. The correlation of the Al composition in the Al(x)Ga(1-x)N films with respect to the stress induced in the GaN film grown was studied using high-resolution x-ray diffraction, including symmetrical and asymmetrical omega/2 theta scans and reciprocal space maps. It is found that with proper design of the Al composition in the Al(x)Ga(1-x)N buffer layer, crack-free GaN film can be successfully grown on 6 in. Si (111) substrates using multilayer AlN and Al(x)Ga(1-x)N buffer layers. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3385672]
Effects of NH3 Flow Rate During AlGaN Barrier Layer Growth on the Material Properties of AlGaN/GaN HEMT Heterostructure
(2017-10-01)
Lumbantoruan, Franky J.
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Wong, Yuen-Yee
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Huang, Wei-Ching
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Yu, Hung-Wei
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Chang, Edward-Yi
NH3 flow rate during AlGaN barrier layer growth not only affects the growth efficiency and surface morphology as a result of parasitic reactions but also influences the concentration of carbon impurity in the AlGaN barrier. Carbon, which decomposes from metal precursors, plays a role in electron compensation for AlGaN/GaN HEMT. No 2-dimensional electron gas (2-DEG) was detected in the AlGaN/GaN structure if grown with 0.5 slm of NH3 due to the presence of higher carbon impurity (2.6 x 10(19) cm(-2)). When the NH3 flow rate increased to 6.0 slm, the carbon impurity reduced to 2.10 x 10(18) atom cm(-3) and the 2 DEG electron density recovered to 9.57 x 10(12) cm(-2).
Effects of the growth temperature on structural and electrical properties of AlN/GaN heterostructures grown by metal organic chemical vapor deposition
(2020-09-01)
Zheng, Xia-Xi
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Lin, Chun-Hsiung
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Ueda, Daisuke
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Chang, Edward-Yi
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交大名義發表
In this paper, we present the dependence of structural and electrical properties of AlN/GaN heterostructure on the growth temperature on sapphire substrates by metal organic chemical vapor deposition. The results revealed that higher Ga incorporation (similar to 47%) and higher trench density on the surface of AlN barrier layer when grown at 1125 degrees C. However, further decreasing the AlN growth temperature to 500 degrees C results in the lower Ga incorporation (similar to 5%), higher dislocation density, 3D island growth and larger tensile strain of AlN barrier layer. Degradation of structural properties and surface morphologies AlN barrier layer results in the higher resistivity of 2-dimensional electron gas transport properties. Low sheet resistance (255.45 Omega/sq), high free carrier electron density (2.86 x 10(13) cm(-2)), simultaneously maintaining low surface roughness and high crystal quality of AlN barrier were achieved at optimized growth temperature around 800 degrees C.
Evaluation of Cu-bumps with lead-free solders for flip-chip package applications
(2009-12-01)
Lin, Kung-Liang
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Chang, Edward-Yi
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Shih, Lin-Chi
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材料科學與工程學系
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Department of Materials Science and Engineering
Low cost electroplated Cu-bump with environmental friendly Sn solder was developed for flip-chip applications. The seed layer used was Ti/WN(x)/Ti/Cu where WN(x) was used as the Cu diffusion barrier and Ti was used to enhance the adhesion between bump and the chip pad. Thick negative photoresist (THB JSR-151N) with a high aspect ratio of 2.4 was used for electroplating of copper bump and Sn solder. The Sn solder cap was reflowed at 225 degrees for 6 min at N(2) atmosphere. No wetting phenomenon was observed for the Sn solder as evaluated by energy-dispersed spectroscopy (EDS). The Cu-bump with Ti/WN(x)/Ti/Cu seed layer not only have higher shear force than the Cu-bump with Ti/Cu seed layer but also has higher resistance to fatigue failure than the Au, SnCu, SnAg bumps. (C) 2009 Elsevier B.V. All rights reserved.
Fabrication and characterization of n-In0.4Ga0.6N/p-Si solar cell
(2012-07-01)
Tran, Binh-Tinh
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Chang, Edward-Yi
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Trinh, Hai-Dang
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Lee, Ching-Ting
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Sahoo, Kartika Chandra
Electro-optic characteristics of a fabricated n-In0.4Ga0.6N/p-Si hetero-structure solar cell on Si substrate with Al and ITO (or Ti/Al/Ni/Au) materials for p and n-type contacts were investigated in this letter. The solar cell devices with ITO as n-type contacts were also compared to the solar cell using Ti/Al/Ni/Au as n-type contact in this study. High short-circuit current density observed for solar cell with ITO as n-type contacts due to the increased amount of light reaching the solar cell. The device with ITO contact exhibited an open-circuit voltage (V-oc) of 1.52 V and a short-circuit current density (J(sc)) of 8.68 mA/cm(2) with 54% fill factor. The conversion and external quantum efficiency (EQE) of the solar cell were 7.12 and 20.8%, respectively. Besides, a relationship between V-oc and In content in the InxGa1-xN alloys for this type of solar cell was also derived. (C) 2012 Elsevier B.V. All rights reserved.
Fabrication of Antireflective Sub-Wavelength Structures on Silicon Nitride Using Nano Cluster Mask for Solar Cell Application
(2009-07-01)
Sahoo, Kartika Chandra
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Lin, Men-Ku
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Chang, Edward-Yi
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Lu, Yi-Yao
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Chen, Chun-Chi
We have developed a simple and scalable approach for fabricating sub-wavelength structures (SWS) on silicon nitride by means of self-assembled nickel nanoparticle masks and inductively coupled plasma (ICP) ion etching. Silicon nitride SWS surfaces with diameter of 160-200 nm and a height of 140-150 nm were obtained. A low reflectivity below 1% was observed over wavelength from 590 to 680 nm. Using the measured reflectivity data in PC1D, the solar cell characteristics has been compared for single layer anti-reflection (SLAR) coatings and SWS and a 0.8% improvement in efficiency has been seen.
Growth and Fabrication of GaN Light Emitting Diode on Patterned-Sapphire Substrate
(2013-01-01)
Binh-Tinh Tran
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Ming, Chen-Hauw
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Lin, Kung-Liang
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Chen, Hao-Ming
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Wang, Ching-Chian
In this study, the growth of GaN-films-based light emitting diodes (LEDs), have been clearly demonstrated on wet-etching patterned sapphire substrate (PSS) and conventional LEDs. The wet-etching PSS LED device showed a significantly higher performance than the conventional LED device. The wet-etching PSS LED device exhibited a leakage current of 9 mA under a bias of 8 V, an external quantum efficiency and output powers of 35.09 % and 19.23 mW under 20 mA injection current as compared to 12 mA, 27.23%, and 15.02 mW of the conventional LED device.
Growth of GaN film on 150 mm Si (111) using multilayer AlN/AlGaN buffer by metal-organic vapor phase epitaxy method
(2007-11-26)
Lin, Kung-Liang
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Chang, Edward-Yi
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Hsiao, Yu-Lin
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Huang, Wei-Ching
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Li, Tingkai
High quality GaN film was successfully grown on 150 mm Si (111) substrate by metal-organic vapor phase epitaxy method using AlN multilayer combined with graded AlGaN layer as buffer. The buffer layer structure, film quality, and film thickness are critical for the growth of the crack-free GaN film on Si (111) substrate. Using multilayer AlN films grown at different temperatures combined with graded Al(1-x)Ga(x)N film as the buffer, the tensile stress on the buffer layer was reduced and the compressive stress on the GaN film was increased. As a result, high quality 0.5 mu m crack-free GaN epitaxial layer was successfully grown on 6 in. Si substrate. (C) 2007 American Institute of Physics.
Growth of GaN films on circle array patterned Si (111) substrates
(2014-09-01)
Lin, Kung-Liang
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Binh Tinh Tran
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Chung, Chen-Chen
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Chang, Edward-Yi
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材料科學與工程學系
Low stress, low defect density GaN was successfully grown on circle array patterned Si (111) substrate using AlN as the buffer followed by two steps growth of the GaN film. Raman measurement shows a reduction of in plane biaxial stress for the GaN film grown on patterned substrate. The slight blueshifL of PL peaks further provides evidence that the tensile stress in the GaN film was relaxed, It is believed that the grain boundaries of the polycrystalline AlN buffer layer and the dislocations in the GaN film grown helped to relieve the stress induced by the lattice and the thermal coefficient mismatches during growth. (C) 2014 Elsevier By. All rights reserved.
Growth of High-Quality In(0.4)Ga(0.6)N Film on Si Substrate by Metal Organic Chemical Vapor Deposition
(2011-11-01)
Binh-Tinh Tran
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Chang, Edward-Yi
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Lin, Kung-Liang
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Wong, Yuen-Yee
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Sahoo, Kartika Chandra
High-quality In(0.4)Ga(0.6)N film grown on GaN/AlN/Si(111) templates was obtained by metal organic chemical vapor deposition (MOCVD) with negligible phase separation. A template of high-quality GaN grown on a Si(111) substrate using AlN buffer layers was used for subsequent In(0.4)Ga(0.6)N growth. The GaN layer was 0.6 mu m thick with rocking-curve full width at half maximum (FWHM) for a GaN(002) peak better than 430 arcsec. The In(0.4)Ga(0.6)N film grown was 0.3 mu m thick with a dislocation density of 6 x 10(7) cm(-2) and X-ray (omega-2 theta) FWHM better than 130 arcsec. (C) 2011 The Japan Society of Applied Physics
Growth of High-Quality In0.4Ga0.6N Film on Si Substrate by Metal Organic Chemical Vapor Deposition
(2011-11-01)
Binh-Tinh Tran
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Chang, Edward-Yi
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Lin, Kung-Liang
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Wong, Yuen-Yee
;
Sahoo, Kartika Chandra
High-quality In0.4Ga0.6N film grown on GaN/AlN/Si(111) templates was obtained by metal organic chemical vapor deposition (MOCVD) with negligible phase separation. A template of high-quality GaN grown on a Si(111) substrate using AlN buffer layers was used for subsequent In0.4Ga0.6N growth. The GaN layer was 0.6 mu m thick with rocking-curve full width at half maximum (FWHM) for a GaN(002) peak better than 430 arcsec. The In0.4Ga0.6N film grown was 0.3 mu m thick with a dislocation density of 6 x 10(7) cm(-2) and X-ray (omega-2 theta) FWHM better than 130 arcsec. (C) 2011 The Japan Society of Applied Physics
InAs Thin-Channel High-Electron-Mobility Transistors with Very High Current-Gain Cutoff Frequency for Emerging Submillimeter-Wave Applications
(2013-03-01)
Chang, Edward-Yi
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Kuo, Chien-I
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Hsu, Heng-Tung
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Chiang, Che-Yang
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Miyamoto, Yasuyuki
60 nm InAs high-electron-mobility transistors (HEMTs) with a thin channel, a thin InAlAs barrier layer, and a very high gate stem structure have been fabricated and characterized. The thickness of the channel, as well as that of the InAlAs barrier layer, was reduced to 5 nm. A stem height of 250 nm with a Pt-buried gate was used in the device configuration to reduce the parasitics. A high DC transconductance of 2114 mS/mm and a current-gain cutoff frequency (f(T)) of 710 GHz were achieved at V-DS 0.5V. (C) 2013 The Japan Society of Applied Physics