Browsing by Author "Chu, LH"

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2 V-operated InGaP-AlGaAs-InGaAs enhancement-mode pseudomorphic HEMT
(2005-02-01)
Chu, LH
;
Chang, EY
;
Chen, SH
;
Lien, YC
;
Chang, CY
A low-voltage single power supply enhancement-mode InGaP-AlGaAs-InGaAs pseudomorphic high-electron mobility transistor (PHEMT) is reported for the first time. The fabricated 0.5 x 160 mum(2) device shows low knee voltage of 0.3 V, drain-source current (I-DS) of 375 mA/mm and maximum transconductance of 550 mS/mm when drain-source voltage (V-DS) was 2.5 V. High-frequency performance was also achieved; the cut-off frequency(F-t) is 60 GHz and maximum oscillation frequency(F-max) is 128 GHz. The noise figure of the 160-mum gate width device at 17 GHz was measured to be 1.02 dB with 10.12 dB associated gain. The E-mode InGaP-AlGaAs-InGaAs PHEMT, exhibits a high output power density of 453 mW/mm with a high linear gain of 30.5 dB at 2.4 GHz. The E-mode PHEMT can also achieve a high maximum power added efficiency (PAE) of 70%, when tuned for maximum PAE.
Low-noise metamorphic HEMTs with reflowed 0.1 mu m T-gate
(2004-06-01)
Lien, YC
;
Chang, EY
;
Chang, HC
;
Chu, LH
;
Huang, GW
A 0.1-mum T-gate fabricated using e-beam lithography and thermally reflow process was developed and applied to the manufacture of the low-noise metamorphic high electron-mobility transistors (MHEMTs). The T-gate developed using the thermally reflowed e-beam resist technique had a gate length of 0.1 mum and compatible with the MHEMT fabrication process. The MHEMT manufactured demonstrates a cutoff frequency f(T) of 154 GHz and a maximum frequency f(max). of 300 GHz. The noise figure for the 160 mum gate-width device is less than 1 dB and the associated gain is up to 14 dB at 18 GHz. This is the first report of a 0.1 mum MHEMT device manufactured using the reflowed e-beam resist process for T-gate formation.
Use WNx as diffusion barrier for copper airbridged low noise GaAsPHEMT
(2003-11-27)
Chang, HC
;
Chang, EY
;
Lien, YC
;
Chu, LH
;
Chang, SW
A low noise pseudomorphic high electron mobility transistor (PHEMT) with copper airbridges using sputtered WNx as the diffusion barrier has been developed. Both the material system and the copper airbridged PHEMT with WNx as the diffusion barrier did not decay even after thermal annealing at 250degreesC for 20 h. The results show that the copper airbridges with WNx diffusion barrier can be used as the interconnects for low noise GaAs PHEMTs.