Browsing by Author "Chen, Ke-Shian"

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A Cu-based alloyed ohmic contact system on n-type GaAs
(2007-12-03)
Chen, Ke-Shian
;
Chang, Edward Yi
;
Lin, Chia-Ching
;
Lee, Cheng-Shih
;
Huang, Wei-Ching
An alloyed Pd/Ge/Cu Ohmic contact to n-type GaAs is reported for the first time. The Pd/Ge/Cu Ohmic contact exhibited a very low specific contact resistance of 5.73x10(-7) Omega cm(2) at a low annealing temperature of 250 degrees C. This result is comparable to the reported Pd/Ge and Au/Ge/Ni Ohmic contact systems to n-type GaAs with doping concentrations about 1x10(18) cm(-3). The Ohmic contact formation mechanisms and microstructure evolution were investigated using secondary ion mass spectrometry, x-ray diffraction, transmission electron microscopy, and energy dispersive spectrometer. The Ohmic contact behavior was related to the formation of Cu(3)Ge and PdGa(x)As(y) compounds after annealing. (c) 2007 American Institute of Physics.
A Cu-Metallized InGaP/GaAs Heterojunction Bipolar Transistor with Reliable Pd/Ge/Cu Ohmic Contact for Power Applications
(2010)
Huang, Jui-Chien
;
Lin, Yueh-Chin
;
Tseng, Yu-Ling
;
Chen, Ke-Shian
;
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
Application of Pd/Ge/Cu alloyed ohmic contact system to n-type GaAs for fully Cu-metallized InGaP/GaAs HBTs
(2009-02-01)
Chen, Ke-Shian
;
Chang, Edward Yi
;
Lin, Chia-Ching
;
Lee, Cheng-Shih
;
材料科學與工程學系
Use of the Pd/Ge/Cu multilayers as the emitter and collector ohmic metal for the fully Cu-metallized InGaP/GaAs heterojunction bipolar transistors is studied. The Pd/Ge/Cu ohmic contact exhibited a very low contact resistance of 5.73 x 10(-7) Omega cm(2) at a low annealing temperature (250 degrees C) and the microstructure evolution of Pd/Ge/Cu ohmic contact was investigated using transmission electron microscopy and energy dispersive spectrometer. We also did some comparisons between the Pd/Ge/Cu, Pd/Ge/Ti/Pt/Cu, and the traditional Au/Ge/Ni/Au ohmic contact structures to n-type GaAs. The common emitter I-V curves and Gummel plot of these Cu-metallized HBTs using Pd/Ge/Cu ohmic contact and Cu interconnects showed similar electrical characteristics as those HBTs with conventional Au-metallization. The cutoff frequency (f(T)) of 3 x 20-mu m-emitter-area devices was about 38 GHz. During both the current-accelerated stress test (110 kA/cm(2) stress for 24 h) and the thermal stability test (annealing at 250 degrees C for 24 h), the fully Cu-metallized HBT with Pd/Ge/Cu ohmic contact and Cu interconnects showed almost no obvious degradation in electrical characteristics. The results show that the Pd/Ge/Cu ohmic contact in combination with the Cu interconnects can be used on HBT devices to achieve the Au-free fully Cu-metallized lnGaP/GaAs HBTs, and the devices exhibit good device performance. (C) 2008 Elsevier Ltd. All rights reserved.
Copper metalized ohmic contact electrode of compound device
(2007-07-12)
Lee, Cheng-Shih
;
Chang, Edward Yi
;
Chen, Ke-Shian
The present invention provides an ohmic contact for a copper metallization whose heat diffusion is improved and cost is reduced. Therein, the ohmic contact is formed through a depositing and an annealing of three metal layers of Pd, Ge and Cu; and, the contact resistance of the ohmic contact is adjusted by the thicknesses of the three layers.
Fully Cu-metallized III-V group compound semiconductor device with palladium/germanium/copper ohmic contact system
(2009-08-06)
CHANG, Edward Yi
;
Chen, Ke-Shian
The present invention discloses a fully Cu-metallized III-V group compound semiconductor device, wherein the fully Cu-metallized of a III-V group compound semiconductor device is realized via using an N-type gallium arsenide ohmic contact metal layer formed of a palladium/germanium/copper composite metal layer, a P-type gallium arsenide ohmic contact metal layer formed of a platinum/titanium/platinum/copper composite metal layer, and interconnect metals formed of a titanium/platinum/copper composite metal layer. Thereby, the fabrication cost of III-V group compound semiconductor devices can be greatly reduced, and the performance of III-V group compound semiconductor devices can be greatly promoted. Besides, the heat-dissipation effect can also be increased, and the electric impedance can also be reduced.