Low Turn-on voltage InGaP/GaAsSb/GaAs DHBT Grown by MOCVD
C.H. Huang, Y.C. Chin, M.N. Jseng, C.H. Lin and Michael.H.T. Yang
Visual Photonics Exitaxy Co. Ltd., No. 16, King Yeh 1st Road, Ping-Jen city, 324 Taoyuan, Taiwan, ROC
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Keywords: InGaP, GaAsSb, DHBT, SHBT
In this work, and InGaP/GaAsSb/GaAs DHBT with carbon doping up to 4E19/cm3 GaAsSb base was studied. A current gain of 115 at the collector current density of 25KA/cm2 was achieved for the Rbs of about 530ohm/sq. Over 100mV turn-on voltage and knee voltage reduction and 2/3 offset voltage were obtained for the GaAsSb based HBT compared with the standard InGaP/GaAs SHBT. The DC gain of the device is less temperature dependence (the DC gain variation is less than 3% for the temperature range from 25 degree C to 100 degree C.) due to the larger valence band discontinuity between InGaP emitter and GaAsSb base, compare with the standard InGaP/GaAs SHBT. These results indicate that GaAsSb is a great choice for the base materials of a low turn-on voltage HBT.