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Proceedings Paper

Effect of InAlAs emitter on the microwave performance of InAlAs/InGaAs abrupt npn heterojunction bipolar transistor
Author(s): Saied Tadayon; Bijan Tadayon; Lester Fuess Eastman
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Paper Abstract

Npn InAlAs/lnGaAs abrupt heterojunction bipolar transistor (HBT) structures were grown on nP substrates, by the molecular beam epitaxy (MBE). Transistors were fabricated by using a nonself-aligned technology which uses a selective wet etching to reach the base layer. DC measurement showed that the base current was dominated by the depletion region recombination in the base-emitter junction. CV measurement showed a lot of defects in the heavily compensated InAlAs emitter. The collector current densities for the different layers correlated with the CV measurement results. The microwave measurements on the 4 pm x 5 im emitter lnAlAs /lnGaAs HBT resulted in f and max of 47 GHz and 27 GHz, respectively. The bias scan and the S-parameter measurement showed that the microwave performance of the device was limited by the parasitic resistance in the emitter, which was much bigger than the emitter contact resistance. This extra emitter resistance was due to the undepleted and heavily compensated lnAIAs emitter. A physical small signal circuit model showed that in the absence of this extra emitter resistance, f would become more than 70 GHz. A much better performance is expected with a higher InAlAs emitter dopings, such as 1 xl O8 cm3, which reduces the extra parasitic resistance in the InAlAs emitter significantly.

Paper Details

Date Published: 1 August 1990
PDF: 12 pages
Proc. SPIE 1288, High-Speed Electronics and Device Scaling, (1 August 1990); doi: 10.1117/12.20909
Show Author Affiliations
Saied Tadayon, Cornell Univ. (United States)
Bijan Tadayon, Cornell Univ. (United States)
Lester Fuess Eastman, Cornell Univ. (United States)

Published in SPIE Proceedings Vol. 1288:
High-Speed Electronics and Device Scaling
Lester Fuess Eastman, Editor(s)

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