Browsing by Author "Huang, CE"

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Comparison of InGaP/InGaAs/GaAs and InGaPtInGaAs/AlGaAs pseudomorphic high electron mobility transistors
(2001-12-01)
Huang, CE
;
Lee, CP
;
Huang, RT
;
Chang, MCF
;
電子工程學系及電子研究所
We have studied the DC and RF characteristics of InGaP/InGaAs/AlGaAs and InGaP/InGaAs/GaAs pseudomorphic high electron mobility transistors (PHEMTs). The InGaP gate barrier provides adequate carrier confinement for the channel carriers and at the same time eliminates the problems associated with AlGaAs. Excellent device performance was obtained for both types of devices. No short channel effect was observed at a gate length as low as 0.3 mum. The InGaP/InGaAs/AlGaAs PHEMTS are superior in that they have higher transconductance, higher current carrying capability and better RF performance. This is attributed to the better carrier confinement at the back channel. These results demonstrate that InGaP/InGaAs/AlGaAs PHEMTs are favorable candidates for microwave applications.
Critical spacing between emitter and base in InGaP heterojunction bipolar transistors (HBTs)
(2002-10-01)
Huang, CE
;
Lee, CP
;
Liang, HC
;
Huang, RT
;
電子工程學系及電子研究所
In this paper, the influence of the spacing between the emitter and the base on the performance of InGaP heterojunction bipolar transistors (HBT) was experimentally studied. We found that the emitter to base spacing can be reduced to as small as 0.6 mum without causing a significant drop in the current gain. The reduction in emitter-to-base spacing, however, leads to improvement in high-frequency performance and device phase noise. For optimal dc, RF, and low-frequency noise performances, we have determined that a critical spacing of 0.6similar to0.8 mum between the emitter and the base of an InGaP HBT is required.