Browsing by Author "Hsiao, Yu-Lin"

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460-nm InGaN-Based LEDs Grown on Fully Inclined Hemisphere-Shape-Patterned Sapphire Substrate With Submicrometer Spacing
(2009-10-01)
Chang, Chia-Ta
;
Hsiao, Shih-Kuang
;
Chang, Edward Yi
;
Hsiao, Yu-Lin
;
Huang, Jui-Chien
This letter investigates 460-nm InGaN-based light-emitting diodes (LEDs) grown on a hemisphere-shape-patterned sapphire substrate (HPSS) with submicrometer spacing. The full-width at half-maximum of the (102) plane rocking curves for GaN layer grown on a conventional sapphire substrate (CSS) and HPSS are 480 and 262 arcsec, respectively. Such improvement is due to the reduction of the pure edge threading dislocations. At the forward current of 20 mA, the light output power of the LEDs grown on CSS and HPSS were 4.05 and 5.86 mW, respectively. This improvement of 44% light-output power can be attributed to the improved quality of the material and the increase of the light extraction by the fully inclined facets of the HPSS.
An AlGaAs/InGaAs HEMT Grown on Si Substrate with Ge/GexSi1-x Metamorphic Buffer Layers
(2008)
Chang, Edward Yi
;
Lin, Yueh-Chin
;
Hsiao, Yu-Lin
;
Hsieh, Y. C.
;
Chang, Chia-Yuan
An AlGaAs/InGaAs HEMT grown on Si substrate with Ge/GexSi1-x buffer is demonstrated. The Ge/GexSi1-x metamorphic buffer layer used in this structure was only 1.0 mu m thick. The electron mobility in the In0.18Ga0.82As channel of the HEMT sample was 3,550 cm(2)/Vs. After fabrication, the HEMT device demonstrated a saturation current of 150 mA/mm and a maximum transconductance of 155 mS/mm. The well behaved characteristics of the HEMT device on the Si substrate are believed to be due to the very thin buffer layer achieved and the lack of the antiphase boundaries (APBs) formation and Ge diffusion into the GaAs layers. Index Terms: HEW GaAs on Si, SiGe buffer layer
Characterization of AlInN Layer Grown on GaN/Sapphire Substrate by MOCVD
(2013-02-01)
Huang, Wei-Ching
;
Chang, Edward-Yi
;
Wong, Yuen-Yee
;
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.
DC and RF Performance Improvement of 70 nm Quantum Well Field Effect Transistor by Narrowing Source-Drain Spacing Technology
(2010)
Kuo, Chien-I
;
Hsu, Heng-Tung
;
Chang, Edward Yi
;
Miyamoto, Yasuyuki
;
Wu, Chien-Ying
A 70 nm InAs channel quantum well field effect transistor (QWFET) fabricated by a narrowing source-drain (S/D) spacing technique was realized for future high-speed and logic applications. The S/D spacing was decreased from 3 to 0.65 mu m through a simple fabrication process, which is an ameliorative redeposition ohmic technique. The drain-source current density and transconductance of the device were increased from 391 to 517 mA/mm and from 946 to 1348 mS/mm after the scaling of the S/D spacing, respectively. In addition, the current gain cutoff frequency (f(T)) was also increased from 185 to 205 GHz. These results show that the easy method can effectively improve the III-V QWFET device performance for high-frequency and high-speed applications. (C) 2010 The Japan Society of Applied Physics
Effect of Graded AlxGa1-xN Interlayer Buffer on the Strain of GaN Grown on Si (111) Using MOCVD Method
(2008)
Lin, KungLiang
;
Chang, Edward-Yi
;
Li, Tingkai
;
Huang, Wei-Ching
;
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 Graded AlxGa1-xN Layers on the Properties of GaN Grown on Patterned Si Substrates
(2012-02-01)
Hsiao, Yu-Lin
;
Lu, Lung-Chi
;
Wu, Chia-Hsun
;
Chang, Edward Yi
;
Kuo, Chien-I
2.2-mu m-thick crack-free GaN films were grown on patterned Si substrates. The crack-free GaN films were obtained by patterning Si substrate and optimizing the graded AlxGa1-xN layers. With the increase of the graded AlxGa1-xN layer thickness, the GaN crystal quality improved as judged from the X-ray diffraction data. By applying multi-AlxGa1-xN layers on the patterned Si substrate, a 31% reduction of tensile stress for the GaN film was obtained as measured by micro-Raman. For the AlGaN/GaN high electron mobility transistor grown on 1 x 1 cm(2) larger patterns, the device exhibits maximum drain current density of 776 mA/mm and maximum transconductance of 101 mS/mm. (c) 2012 The Japan Society of Applied Physics
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
;
Chang, Edward-Yi
;
Hsiao, Yu-Lin
;
Huang, Wei-Ching
;
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]
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
;
Chang, Edward-Yi
;
Hsiao, Yu-Lin
;
Huang, Wei-Ching
;
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.
Investigation of the Inserted LT-AlGaN Interlayer in AlGaN/GaN/AlGaN DH-FET Strucutre on Si Substrates
(2014-01-01)
Hsiao, Yu-Lin
;
Chang, Chia-Ao
;
Chang, Edward Yi
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材料科學與工程學系
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Department of Materials Science and Engineering
A novel AlGaN/GaN/AlGaN double-heterostructure field effect transistor (DH-FET) structure with an inserted LT-AlGaN interlayer grown on 150 mm Si substrate has been studied. The DH-FET structure has been characterized by transmission electron microscopy (TEM), secondary ion mass spectrometry (SIMS) and X-ray diffraction (XRD). It is found that the inserted LT-AlGaN interlayer can further induce the compressive stress to compensate the tensile stress. Furthermore, the inserted LT-AlGaN interlayer acts as a dislocation filter to reduce threading dislocation propagation. These results indicate that the inserted LT-AlGaN interlayer plays an important role in the novel DH-FET structure.
Investigation of the low-temperature AlGaN interlayer in AlGaN/GaN/AlGaN double heterostructure on Si substrate
(2014-11-01)
Hsiao, Yu-Lin
;
Wang, Yi-Jie
;
Chang, Chia-Ao
;
Weng, You-Chen
;
Chen, Yen-Yu
A low-temperature (LT) AlGaN interlayer is inserted in the Al0.1Ga0.9N back barrier layer of an Al0.2Ga0.8N/GaN/Al0.1Ga0.9N double heterostructure grown on a 150mm Si substrate. It is found that the 21-nm-thick LT-AlGaN interlayer plays an important role in stress relaxation and dislocation reduction of the Al0.1Ga0.9N back barrier layer, especially for screw dislocation reduction. In addition, a buffer breakdown voltage higher than 600V is achieved, which is much higher than those of conventional heterostructures. These results demonstrate the effectiveness of combining the LT-AlGaN interlayer and the Al0.2Ga0.8N/GaN/Al0.1Ga0.9N double heterostructure on a Si substrate to increase the breakdown voltage for high-power applications. (C) 2014 The Japan Society of Applied Physics
Material growth and device characterization of AlGaN/GaN single-heterostructure and AlGaN/GaN/AlGaN double-heterostructure field effect transistors on Si substrates
(2014-05-01)
Hsiao, Yu-Lin
;
Chang, Chia-Ao
;
Chang, Edward Yi
;
Maa, Jer-Shen
;
Chang, Chia-Ta
An Al0.2Ga0.8N/GaN/Al0.1Ga0.9N double-heterostructure field effect transistor (DH-FET) structure was grown on a 150-mm-diameter Si substrate and the crystalline quality of the epitaxial material was found to be comparable to that of an Al0.2Ga0.8N/GaN single-heterostructure field effect transistor (SH-FET) structure. The fabricated DH-FET shows a lower buffer leakage current of 9.2 x 10(-5) mA/mm and an improved off-state breakdown voltage of higher than 200V, whereas the SH-FET shows a much higher buffer leakage current of 6.0 x 10(-3) mA/mm and a lower breakdown voltage of 130 V. These significant improvements show that the Al0.2Ga0.8N/GaN/Al0.1Ga0.9N DH-FET is an effective structure for high-power electronic applications. (C) 2014 The Japan Society of Applied Physics
MOVPE high quality GaN film grown on Si (111) substrates using a multilayer AlN buffer
(2008)
Lin, Kung-Liang
;
Chang, Edward-Yi
;
Huang, Jui-Chien
;
Huang, Wei-Ching
;
Hsiao, Yu-Lin
High quality GaN films were successfully grown on Si (111) substrates using the MOVPE method and a multilayer AlN buffer. The buffer layer film quality and thickness are critical for the growth of the crack-free GaN film on Si (111) substrates. Cracks started to form on the single layer high temperature (HT) AlN film, grown on Si (111) substrate as the AlN thickness was greater than 20 nm. However, a 100 nm crack-free AlN film, can be obtained when multilayer buffer of HT-AlN/low temperature (LT)-AlN/HT-AlN was grown on the Si(111) substrate. By using multilayer AlN buffer, a 2 mu m crack-free GaN film was successful grown on the 2 '' Si (111) substrate. Moreover, the GaN film (2 mu m thick) grown on Si with a GaN (004) Mosaic FWHM of only 0.12 degrees.
Parallel Prioritized Flow Scheduling for Software Defined Data Center Network
(2013)
Ke, Bo-Yu
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Tien, Po-Lung
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Hsiao, Yu-Lin
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Prioritized flow scheduling is essential for providing QoS differentiation and energy saving in data center network. While dynamically manipulating the routing paths of incoming flows becomes practical via enabling technology of software-defined network (SDN), scheduling a large amount of flows in real time remains challenging. In this paper, we propose an Iterative Parallel Grouping Algorithm (IPGA) to the prioritized flow-scheduling problem. Thanks to the inherent nature of parallelism, the IPGA-based flow scheduler not only performs fast scheduling but also can be efficiently realized by a CUD A system within the SDN controller. Via simulations, we demonstrate that the IPGA scheduler achieves QoS differentiation and promising energy saving for a Fat-tree-based network.
Performance Improvements of AlGaN/GaN HEMTs by Strain Modification and Unintentional Carbon Incorporation
(2015-03-01)
Tien-Tung Luong
;
Binh Tinh Tran
;
Ho, Yen-Teng
;
Minh-Thien-Huu Ha
;
Hsiao, Yu-Lin
An advanced AlGaN/GaN HEMT structure, grown on a sapphire substrate by MOCVD utilizing a high temperature (HT) AN interlayer (IL) and a multilayer high-low-high temperature (HLH) AN buffer layer, demonstrates a superior performance both in breakdown voltage (>200 V) and maximum drain current (Ipss = 667 mA/mm). The HT AN IL produces an additional compressive strain into the above GaN layer. Accordingly, an AlGaN barrier, grown on the more compressive GaN, introduces less tensile strain leading to an improvement in surface morphology (RMS = 0.19 nm in 2 x 2 mu m(2)), a remarkable increase in 2DEG mobility by 46% (mu(S)= 1900 cm(2)/Vs) and a decrease in densities of defects acting as paths for the leakage current through the AlGaN barrier. A high semi-insulating buffer is achieved by eliminating leakage paths both through the buffer layer and the buffer-substrate interfacial layer. These result from an increase in unintentional carbon introduced by AIN layers, especially by a low temperature AN layer; which are grown under low pressure (50 Ton). Lastly, the decrease in AlGaN barrier tensile strain and low leakage current in the advanced HEMTs structure using an HT AN IL and an HLH AIN buffer are promising for an improvement in AlGaN/GaN HEMTs\' reliability.
The growth of pine-leaf-like hierarchical SnO2 nanostructures
(2014-01-01)
Dee, Chang Fu
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Tiong, Teck Yaw
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Varghese, Binni
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Sow, Chorng-Haur
;
Wong, Yuan-Yee
Pine-leaf-like SnO2 hierarchical nanostructures (NSs) were grown by a two-step vapour transport deposition process with a combination of vapour-solid and vapour-liquid-solid mechanisms at the primary and secondary processes, respectively. This type of hierarchical structure consisted of SnO2 trunk with homo-branching nanowires (NWs). The branched NWs connected the trunk NWs at included angles of 56 degrees and 90 degrees for two different types of hierarchical NSs. Based on the thermodynamic calculation, the formation of branched NWs at those angles are all energetically favourable.
The growth of pine-leaf-like hierarchical SnO2 nanostructures
(2014-01-01)
Dee, Chang Fu
;
Tiong, Teck Yaw
;
Varghese, Binni
;
Sow, Chorng-Haur
;
Wong, Yuan-Yee
Pine-leaf-like SnO2 hierarchical nanostructures (NSs) were grown by a two-step vapour transport deposition process with a combination of vapour-solid and vapour-liquid-solid mechanisms at the primary and secondary processes, respectively. This type of hierarchical structure consisted of SnO2 trunk with homo-branching nanowires (NWs). The branched NWs connected the trunk NWs at included angles of 56 degrees and 90 degrees for two different types of hierarchical NSs. Based on the thermodynamic calculation, the formation of branched NWs at those angles are all energetically favourable.