Browsing by Author "Weng, You-Chen"

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Enhancement of electron transport properties of InAlGaN/AlN/GaN HEMTs on silicon substrate with GaN insertion layer
(2020-06-01)
Kao, Min-Lu
;
Ha, Minh Thien Huu
;
Lin, Yuan
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Weng, You-Chen
;
Hsu, Heng-Tung
InAlGaN/AlN/GaN high electron mobility transistors (HEMTs) on a silicon substrate with high electron mobility is demonstrated for the first time. The InAlGaN/AlN/GaN heterostructures has a high electron mobility of 1540 cm(2) V-1 s(-1) and low sheet resistance of 228.2 omega sq(-1) by inserting a thin GaN interlayer (IL) between InAlGaN and AlN layers. The experimental results demonstrate that an optimized GaN IL contributes to a better atomic arrangement of the InAlGaN barrier layer in the InAlGaN/GaN HEMTs and results in better electron transport properties for the device. The InAlGaN/GaN device with 170 nm gate and 2 mu m source-to-drain distance shows a high maximum current density (I-max) of 1490 mA mm(-1) and high transconductance (g(m)) of 401 mS mm(-1). Such results demonstrate the potential of adopting InAlGaN/GaN heterostructure on silicon for low cost mm-wave applications in the future.
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
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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
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Maa, Jer-Shen
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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
RF loss mechanisms in GaN-based high-electron-mobility-transistor on silicon: Role of an inversion channel at the AlN/Si interface
(2017-07-01)
Luong, Tien Tung
;
Lumbantoruan, Franky
;
Chen, Yen-Yu
;
Ho, Yen-Teng
;
Weng, You-Chen
One of the epitaxial issues pertaining to the growth of AlGaN/GaN HEMTs on Si is the decrease of parasitic losses that can adversely impact the RF device performances. We characterized the microwave losses in coplanar waveguides (CPWs) on GaN-based high-electron-mobility-transistors (HEMTs) and their buffer layers on Silicon substrate, up to 40GHz. The RF losses depend not only on the crystalline quality but also on the residual tensile stress in AlN buffer, as well as its thickness. The mechanism of interfacial lossy channel induced by the piezoelectric field is discussed. Adopting a thin high-low-high temperature (HLH) AlN buffer can help to reduce the tensile stress leading to a reduction of RF losses. We suggest that a thinner p-type AlN and/or p-AlGaN-on-thin AlN near the interface can suppress the electron interfacial lossy channel, which helps the GaN-HEMT-on-HR Si to remain in a high frequency range and at high-temperature operation. (C) 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim