Browsing by Author "Kuo, Chien-I"

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30-GHz Low-Noise Performance of 100-nm-Gate-Recessed n-GaN/AlGaN/GaN HEMTs
(2010-02-01)
Chang, Chia-Ta
;
Hsu, Heng-Tung
;
Chang, Edward Yi
;
Kuo, Chien-I
;
Huang, Jui-Chien
We demonstrate a 100-nm-gate-recessed n-GaN/AlGaN/GaN high-electron mobility transistor (HEMT) with low-noise properties at 30 GHz. The recessed GaN HEMT exhibits a low ohmic-contact resistance of 0.28 Omega . mm and a low gate leakage current of 0.9 mu A/mm when biased at V(GS) = -3 V and V(DS) = 10 V. At the same bias point, a minimum noise figure of 1.6 dB at 30 GHz and an associated gain of 5 dB were achieved. To the best of our knowledge, this is the best noise performance reported at 30 GHz for gate-recessed AlGaN/GaN HEMTs.
A 40-nm-Gate InAs/In(0.7)Ga(0.3)As Composite-Channel HEMT with 2200 mS/mm and 500-GHz f(T)
(2009)
Kuo, Chien-I
;
Hsu, Heng-Tung
;
Wu, Chien-Ying
;
Chang, Edward Yi
;
Miyamoto, Yasuyuki
A 40-nm T-gate high-electron-mobility-transistor with InAs/In(0.7)Ga(0.3)As composite-channel has been fabricated. The device exhibits a transconductance (g.) of 2200 mS/mm, a cutoff frequency f(T) of 506 GHz and a minimum noise figure of 1.21 dB at a frequency of 58 GHz. These performances make the device well-suited for millimeter-wave or sub-millimeter-wave applications.
A Novel Metamorphic High Electron Mobility Transistors with (In(x)Ga(1-x)As)(m)/(InAs)(n) Superlattice Channel Layer for Millimeter-Wave Applications
(2009)
Kuo, Chien-I
;
Hsu, Heng-Tung
;
Lu, Jung-Chi
;
Chang, Edward Yi
;
Wu, Chien-Ying
High performance MHEMTs using (In(x)Ga(1-x)As)(m)/(InAs)(n) superlattice structure as a channel layer have been fabricated successfully. These HEMTs with 80 nm gate length exhibit high drain current density of 392 mA/mm at drain bias 1.0 V and transconductance of 991 mS/mm at drain bias 1.2 V. Comparison with regular In(x)Ga(1-x)As channel, the superlattice channel HEMTs show an outstanding performance because of high electron mobility, and better carrier confinement in the (In(x)Ga(1-x)As)(m)/(InAs)(n) channel layer. The current gain cutoff frequency (f(T)) and maximum oscillation frequency (f(max)) were extracted to be 304 GHz and 162 GHz, respectively. The device demonstrated a 0.75 dB noise figure with an associated gain 9.6 dB at 16 GHz. The excellent device performance shows that the superlattice channel can be practically used for high-frequency and millimeter-wave application.
An 80 nm In(0.7)Ga(0.3)As MHEMT with Flip-Chip Packaging for W-Band Low Noise Applications
(2010-01-01)
Wang, Chin-Te
;
Kuo, Chien-I
;
Lim, Wee-Chin
;
Hsu, Li-Han
;
Hsu, Heng-Tung
The fabrication process of an 80 nm In(0.7)Ga(0.3)As MHEMT device with flip-chip packaging on Al(2)O(3) substrate is presented. The flip-chip packaged device exhibited good dc characteristics with high I(DS) = 425 mA/mm and high g(m) = 970 mS/mm at V(DS) = 1.5 V. Besides, the RF performances revealed high gain of 10 dB at 50 GHz and low minimum noise figure (NF(min))below 2 dB at 60 GHz, showing the feasibility of flip-chip packaged In(0.7)Ga(0.3)As MHEMT device for low noise applications at W-band.
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
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
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 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
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
Evaluation of RF and Logic Performance for 40 nm InAs/InGaAs Composite Channel HEMTs for high-speed and low-voltage applications
(2008)
Wu, Chien-Ying
;
Hsu, Heng-Tung
;
Kuo, Chien-I
;
Chang, Edward Yi
;
Chen, Yu-lin
The DC and RF performances of 40 nm high electron mobility transistors (HEMTs) with composite channel of InAs channel and In(0.53)Ga(0.47)As sub-channel were demonstrated. The drain current was 870 mA/mm (V(ds)=0.4V, V(gs) OV) and maximum g(m) was 1750 mS/mm (V(ds)=0.5V, V(gs)=-0.65V). The devices showed high current gain cutoff frequency (f(T)) of 420 GHz and low gate delay time of 0.77 ps owing to the nanometer gate length and extremely high electron mobility of the InAs channel. Under low DC power consumption; these InAS HEMTs still exhibited excellent RF and logic performance which indicates these devices have great potential for future high-speed and low-voltage applications.
Evaluation of RF and logic performance for 80 nm InAs/InGaAs composite channel HEMTs using gate sinking technology
(2007)
Kuo, Chien-I
;
Hsu, Heng-Tung
;
Chang, Chia-Yuan
;
Chang, Edward Yi
;
Hsu, Heng-Shou
80-nm-gate In(0.7)Ga(0.3)As/InAs/In(0.7)Ga(0.3)As composite channel high-electron mobility transistors (HEMTs) fabricated using platinum (Pt) buried gate as the Schottky contact metal were evaluated for RF and logic application. After gate sinking at the 250 degrees C for 3 minutes, the device exhibited a high g. value of 1590mS/mm at V(d) = 0.5V and the current gain cutoff frequency f(T) was measured to be 494 GHz. The intrinsic gate delay time was calculated to be 0.78 psee at supply voltage of 0.6 V. This is the highest f(T) achieved for 80 nm gate length HEMT devices. These superior performances are attributed to the reduction of distance between. gate and channel, and the reduction of parasitic gate capacitances during gate-sinking process.
Flip-Chip Packaging of In0.6Ga0.4As MHEMT Device on Low-Cost Organic Substrate for W-Band Applications
(2010)
Lim, Wee Chin
;
Wang, Chin-Te
;
Kuo, Chien-I
;
Hsu, Li-Han
;
Tsai, Szu-Ping
A discrete low noise In0.6Ga0.4As MHEMT device with 150 nm gate length was flip-chip assembled on the low-cost RO3210 organic substrate for wireless communication applications. The measured DC characteristics were very similar before and after flip-chip assembly. The flip-chip packaged MHEMT device showed a high drain current density of 516 mA/mm and a maximum transconductance of 576 mS/mm at a V-DS of 0.8 V. The insertion gain of the flip-chip packaged device was decayed less than 2 dB up to 100 GHz as compared to the data of bare die. Moreover, the measured minimum noise figure was less than 2 dB as measured at V-DS of 0.7 V and V-GS of -0.7 V in the frequency range from 20 to 64 GHz for the device after flip-chip assembly. The excellent performance of the flip-chip packaged MHEMT device demonstrates the feasibility of using low cost organic substrate for high frequency applications up to W band.
Flip-Chip Packaging of Low-Noise Metamorphic High Electron Mobility Transistors on Low-Cost Organic Substrate
(2011-09-01)
Wang, Chin-Te
;
Kuo, Chien-I
;
Hsu, Heng-Tung
;
Chang, Edward Yi
;
Hsu, Li-Han
The rapid growth of high-frequency wireless communication demands high-performance packaging structures at low cost. A flip-chip interconnect is one of the most promising technologies owing to its low parasitic effect and high performance at high frequencies. In this study, the in-house fabricated In(0).(6)Ga(0.4)As metamorphic high electron mobility transistor (mHEMT) device was flip-chip-assembled using a commercially available low-cost organic substrate. The packaged device with the optimal flip-chip structure exhibited almost similar DC and RF results to the bare die. An exopy-based underfill was applied to the improvement of reliability with almost no degradation of the electrical characteristics. Measurement results revealed that the proposed packaging structure maintained a low minimum noise figure of 3 dB with 6 dB associated gain at 62 GHz. Such a superior performance after flip-chip packaging demonstrates the feasibility of the proposed low-cost organic substrate for commercial high-frequency applications up to the W-band. (C) 2011 The Japan Society of Applied Physics
Ge epitaxial films on GaAs (100), (110), and (111) substrates for applications of CMOS heterostructural integrations
(2013-03-01)
Tang, Shih-Hsuan
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Kuo, Chien-I
;
Trinh, Hai-Dang
;
Chang, Edward Yi
;
Nguyen, Hong-Quan
Epitaxial Ge films were grown on GaAs (100), (110), and (111) substrates by using ultra-high vacuum chemical vapor deposition and studied with various methods. The incubation times and growth rates were quite different for these three GaAs substrates because the surface arsenic coverage on GaAs and hydrogen desorption energy on Ge are different for each orientation. High-resolution x-ray diffraction measurements, direct band-gap emission of photoluminescence measurements, and cross-sectional transmission electron microscopy showed that the Ge films had high crystal quality, low defect density, and sharp Ge/GaAs interfaces. In this study, atomic force microscopy analysis found that the Ge films grow on GaAs (100) and (111) via the Frank van der Merwe mode, while the Ge film grows on GaAs (110) via the Volmer-Weber mode at the initial growth stage, which can be explained by the thermodynamic theory of capillarity. Interestingly, when the thickness of the Ge film on the GaAs (110) substrate increases to similar to 220 nm, the 3D Ge islands merge and form a smooth surface (rms roughness of 0.3 nm), which is useful for devices. The authors also fabricated Ge metal-oxide-semiconductor capacitors (MOSCAPs) on GaAs (100) and (110) substrates. Both Ge/GaAs (100) and Ge/GaAs (110) MOSCAPs exhibit good capacitance-voltage responses with strong inversion behaviors, which means the grown material has reached device quality. The Ge/GaAs (110) structure especially offers optimal integration of Ge pMOSFETs on GaAs substrates because Ge (110) has a high hole mobility compared with Ge (100) and (111). (C) 2013 American Vacuum Society. [http://dx.doi.org/10.1116/1.4789427]
High-performance In0.52Al0.48As/In0.6Ga0.4As power metamorphic high electron mobility transistor for Ka-band applications
(2007-06-01)
Chang, Chia-Yuan
;
Chang, Edward Yi
;
Lien, Yi-Chung
;
Miyamoto, Yasuyuki
;
Kuo, Chien-I
A 70nm In0.52Al0.48As/In0.6Ga0.4As power metamorphic high electron mobility transistor (MHEMT) with a double delta-doping structure was fabricated and evaluated. The device has a high transconductance of 827mS/mm. The saturated drain-source current of the device is 890mA/mm. A current gain cutoff frequency (f(T)) of 200GHz and a maximum oscillation frequency (f(max)) of 300GHz were achieved owing to the nanometer gate length and high indium content in the channel. When measured at 32 GHz, the 0.07x160 mu m(2) device demonstrates a maximum output power of 14.5dBm (176mW/mm) and a P I dB of 11.1dBm (80mW/mm) with a 9.5dB power gain. The excellent DC and RF performance of the 70mn MHEMT are comparable to those of InP-based HEMTs and show the great potential for Ka-band power applications.
Improvement in RF performance of 40-nm InAs-channel based HEMTs using Pt gate sinking with two-step recess processes technology
(2010-12-01)
Kuo, Chien-I
;
Hsu, Heng-Tung
;
Wu, Chien-Ying
;
Chang, Edward Y.
;
Chen, Yu-Lin
Forty-nanometer lnAs HEMT devices fabricated by two-step recess and Pt-buried gate were demonstrated for low-noise and low-power millimeter wave applications. The device exhibited a high transconductance of 1650 mS/mm at a drain voltage of 0.5 V. Improvement of the current-gain cutoff frequency from 395 GHz to 423 GHz was achieved with minimum noise figure below 2.5 dB up to 64 GHz at only 4.33 mW DC power consumption level. Besides, the output conductance was decreased from 2400 mS/ mm to 325 mS/mm. These superior performances are attributed to mitigation of the short-channel effect through the proposed technology. (C) 2010 Elsevier B.V. All rights reserved.
Improvement on the noise performance of InAs-based HEMTs with gate sinking technology
(2010-11-01)
Hsu, Heng-Tung
;
Kuo, Chien-I
;
Chang, Edward Y.
;
Kuo, Fang-Yao
;
材料科學與工程學系
Improvement on the RF and noise performance for 80 nm InAs/In(0.7)Ga(0.3)As high-electron mobility transistor (HEMT) through gate sinking technology is presented. After gate sinking at 250 degrees C for 3 min, the device exhibited a high transconductance of 1900 mS/mm at a drain bias of 0.5 V with 1066 mA/mm drain-source saturation current. A current-gain cutoff frequency (f(T)) of 113 GHz and a maximum oscillation frequency (f(max)) of 110 GHz were achieved at extremely low drain bias of 0.1 V. The 0.08 x 40 mu m(2) device with gate sinking demonstrated 0.82 dB minimum noise figure and 14 dB associated gain at 17 GHz with only 1.14 mW DC power consumption. Significant improvement in RF and noise performance was mainly attributed to the reduction of gate-to-channel distance together with the parasitic source resistance through gate sinking technology. (C) 2010 Elsevier B.V. All rights reserved.
InAs channel-based quantum well transistors for high-speed and low-voltage digital applications
(2008)
Kuo, Chien-I
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Hsu, Heng-Tung
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Chang, Edward Yi
;
材料科學與工程學系
;
Department of Materials Science and Engineering
High-performance indium arsenic (InAs) channel-based quantum well field-effect transistors (QWFETs) have been fabricated. A superior drain-source current density of 1015 mA/mm was achieved, with a high transconductance of 1900 mS/mm when the drain (V(DS)) was biased at 0.5 V. The current gain cutoff frequency (f(T)) and maximum oscillation frequency (f(max)) were extracted to be 393 and 260 GHz, respectively. A very low gate delay of 0.54 ps was also achieved at a 0.5 V drain bias. Compared to a silicon n-channel metal-oxide semiconductor field-effect transistor, the QWFETs exhibited a better radio-frequency performance with lower dc power consumption, which indicates the great potential for high-speed and low-voltage digital applications. (C) 2008 The Electrochemical Society.
InAs high electron mobility transistors with buried gate for ultralow-power-consumption low-noise amplifier application
(2008-09-01)
Kuo, Chien-I
;
Hsu, Hen-Tung
;
Chang, Edward Yi
;
Miyamoto, Yasuyuki
;
Tsern, Wen-Chung
An InAs/In(0.3)As composite channel high-electron-mobility transistor (HEMT) fabricated using the gate sinking technique was realized for ultralow-power-consumption low-noise application. The device has a very high transconductance of 100 mS/mm at at drain voltage of 0.5 V. The saturated drain-Source current of the device is 1066 mA/mm. A current grin cutoff frequency (f(T)) of 113 GHz and a maximum oscillation frequency (f(max)) of 110GHz were achieved at only drain bias volume V(ds) = 0.1V. The 0.08 x 40 mu m(2) device demonstrated a minimum noise figure of 0.82 dB and a 14 dB associated gain at 17GHz with 1.14mW DC power consumption.
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
;
Kuo, Chien-I
;
Hsu, Heng-Tung
;
Chiang, Che-Yang
;
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