12.5 nm base pseudomorphic heterojunction bipolar transistors achieving fT=710GHz and fMAX=340GHz

Abstract

The pseudomorphic collector structure is known to allow enhanced collector transport, facilitating higher current cutoff frequencies at lower current densities and junction temperatures compared to traditional single heterojunction structures. The performance of a 0.25×3μm2 pseudomorphic heteojunction bipolar transistors achieves peak fT of 710 GHz (fMAX=340GHz) at a collector current density of 20mA∕μm2. The same device achieves a fT∕fMAX of 540∕407GHz at a reduced current density of 7.5mA∕μm2. The epitaxial structure employs a 12.5 nm strained InGaAs base and 55 nm InGaAs collector, and exhibits a β of 115 and breakdown voltage of BVCEO=1.75V.

Self-consistent simulation of array-based CNFETs: Impact of tube pitch on RF performance

“…The values of extrinsic f T , even in the presence of parasitic capacitances, are very promising; the values stand ahead of the reported records for other highfrequency transistors [15][16][17][18], and they surpass the ITRS requirements for RF CMOS [19]. Case II With Screening Case II Without Screening nanotube pitch for for the structures specified in the text.…”

“…7, attainable for pitch values in the tens of nm and the gate length of 20 nm used in this study, stand ahead of the present records for all of the CNFET's competitors: 485 GHz for silicon MOSFETs [15], 644 GHz for III-V high-electron mobility transistors (HEMTs) [16], 300 GHz for graphene transistors [17], and 710 GHz for heterojunction bipolar transistors (HBTs) [18]. For convenience, all the mentioned records have been summarized in Table I. Furthermore, the ITRS peak f T requirement for RF CMOS millimeter-wave (10-100 GHz) technology with the same channel length of 20 nm [19] (for the year 2015) is 440 GHz, which is well below the values potentially attainable from an array-based CNFET, such as the one considered in this study.…”

Improved breakdown voltages for type I InP/InGaAs DHBTs

“…The strained grade of DHBT 40 displays a lower Kirk threshold, possibly related to the 1 nm thin setback, or relaxation related defects induced from the strained growth. As shown in table III, the Kirk threshold of all three grades compare favorably with earlier UCSB DHBTs using longer setback and grades, as well as InGaAs SHBTs [10]. Table III shows experimental data and breakdown simulations for different UCSB DHBT designs, with collector thicknesses ranging from 60nm up to 150 nm.…”

Critique of high-frequency performance of carbon nanotube FETs

“…(2). obtain record f T values for other transistors: Si MOSFETs (330 GHz [10]) and InP/InGaAs HBTs (710 GHz [11]). …”