Browsing by Author "Sahoo, Kartik Chandra"

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InAlAs/InGaAs metamorphic high electron mobility transistor with Cu/Pt/Ti gate and Cu airbridges
(2007-05-01)
Chang, Chun-Wei
;
Chen, Po-Chou
;
Lee, Huang-Ming
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Chen, Szu-Hung
;
Sahoo, Kartik Chandra
The use of a Cu/Pt/Ti Schottky contact structure and Cu-based airbridges for high-frequency metamorphic high electron mobility transistor (MHEMT) is successfully developed. The material characteristics of the Cu/Pt/Ti Schottky contact on i-InAlAs were studied. Judging from the results of the X-ray diffraction analysis, Auger electron spectroscopy, and transmission electron microscopy, the Cu/Pt/Ti Schottky contact structure on InAlAs was very stable after annealing at 350 degrees C. However, after 400 degrees C annealing, the reaction of copper with the layers underneath started to occur and formed the Cu4Ti phase. The Cu-metallized MHEMT using the proposed Cu/Pt/Ti T-gate structure and Cu-based airbridges has a saturated drain current of 673 mA/mm and a maximum transconductance of 750 mS/mm. The gate to drain breakdown voltage measured was 14.5 V at a gate reverse current of -1 mA/mm. The device also demonstrated a cutoff frequency F-t of 90 GHz and a maximum frequency of oscillation F-max of 165 GHz. An MHEMT with a Au/Pt/Ti gate was fabricated and compared with an MHEMT fabricated with the proposed Cu/Pt/Ti gate. These two kinds of MHEMTs showed similar F-t and F-max. These results demonstrate that the Cu/Pt/Ti T-gate and Cu-based airbridges can be used for MHEMT fabrication with excellent electrical characteristics.
RF Performance Improvement of Metamorphic High-Electron Mobility Transistor Using (In(x)Ga(1-x)As)(m)/(InAs)(n) Superlattice-Channel Structure for Millimeter-Wave Applications
(2010-07-01)
Kuo, Chien-I
;
Hsu, Heng-Tung
;
Chen, Yu-Lin
;
Wu, Chien-Ying
;
Chang, Edward Yi
High-performance metamorphic high-electron mobility transistors (MHEMTs) using an (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 exhibited a high drain current density of 392 mA/mm and a transconductance of 991 mS/mm at 1.2-V drain bias. Compared with a regular In(x)Ga(1-x)As channel, the superlattice-channel HEMTs showed an outstanding performance due to the high electron mobility and better carrier confinement in the (In(x)Ga(1-x)As)(m)/(InAs)(n) channel layer. When biased at 1.2 V, the current gain cutoff frequency (f(T)) and the maximum oscillation frequency (f(max)) were extracted to be 304 and 162 GHz, respectively. As for noise performance, the device demonstrated a 0.75-dB minimum noise figure(NF(min)) with an associated gain of 9.6 dB at 16 GHz. Such superior performance has made the devices with a superlattice channel well suitable for millimeter-wave applications.
RF Performance Improvement of Metamorphic High-Electron Mobility Transistor Using (InxGa1-xAs)(m)/(InAs)(n) Superlattice-Channel Structure for Millimeter-Wave Applications
(2010-07-01)
Kuo, Chien-I
;
Hsu, Heng-Tung
;
Chen, Yu-Lin
;
Wu, Chien-Ying
;
Chang, Edward Yi
High-performance metamorphic high-electron mobility transistors (MHEMTs) using an (InxGa1-xAs)(m)/(InAs)(n) superlattice structure as a channel layer have been fabricated successfully. These HEMTs with 80-nm gate length exhibited a high drain current density of 392 mA/mm and a transconductance of 991 mS/mm at 1.2-V drain bias. Compared with a regular InxGa1-xAs channel, the superlattice-channel HEMTs showed an outstanding performance due to the high electron mobility and better carrier confinement in the (InxGa1-xAs)(m)/(InAs)(n) channel layer. When biased at 1.2 V, the current gain cutoff frequency (f(T)) and the maximum oscillation frequency (f(max)) were extracted to be 304 and 162 GHz, respectively. As for noise performance, the device demonstrated a 0.75-dB minimum noise figure(NFmin) with an associated gain of 9.6 dB at 16 GHz. Such superior performance has made the devices with a superlattice channel well suitable for millimeter-wave applications.