Showing posts with label DHBTs. Show all posts
Showing posts with label DHBTs. Show all posts

May 4, 2020

[paper] DHBT with Record ft of 813 GHz

Y. Shiratori, T. Hoshi and H. Matsuzaki,
InGaP/GaAsSb/InGaAsSb/InP Double Heterojunction Bipolar Transistors
With Record ft of 813 GHz
IEEE EDL vol. 41, no. 5, pp. 697-700, May 2020
doi: 10.1109/LED.2020.2982497

Abstract - We fabricated InGaP/GaAsSb/InGaAsSb/InP double heterojunction bipolar transistors (DHBTs) with an aggressive lateral and vertical scaling technology to improve the current gain cutoff frequency (fT) further. A 13-nm-thick GaAsSb/InGaAsSb base and a 40-nm-thick InP collector are used to reduce electron transit time. In addition, the width of the base electrode on each side of the emitter is reduced to about 0.05µm to suppress increases in parasitic collector capacitance. A fabricated DHBT with the emitter size of 0.24µm×7.8 µm exhibits maximum differential current gain of ∼95 and collector-emitter breakdown voltage of 2.6V. At a collector current density of 18 mA/µm2, the DHBT exhibits fT of 813 GHz, which is the highest among all types of transistors measured at a room temperature.
Fig: (a) Current gain ( |h21| ) and Mason’s unilateral power gain (Ug ) of the DHBT as a function of frequency. JC and VCE are 18 mA/μm2 and 1.0 V, respectively. ft and fmax are extrapolated by single-pole fitting. Inset: frequency dependence of extrapolating ft and fmax . (b) Gummel’s ft extraction (imaginary part of 1/h21 as a function of frequency). The red circles and black line show experimental data and a linear fitting, respectively.

URL: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9044299&isnumber=9079222