TY - JOUR
T1 - The upper limit of the cutoff frequency in ultrashort gate-length InGaAs/ InAlAs HEMTs
T2 - A new definition of effective gate length
AU - Akis, Richard
AU - Ayubi-Moak, Jason S.
AU - Faralli, Nicolas
AU - Ferry, David K.
AU - Goodnick, Stephen
AU - Saraniti, Marco
N1 - Funding Information:
Manuscript received November 9, 2007; revised January 25, 2008. This work was supported in part by the DARPA SWIFT project through the Army Research Laboratory under Cooperative Agreement W911NF-06-2-0012. The review of this letter was arranged by Editor J. del Alamo.
PY - 2008/4
Y1 - 2008/4
N2 - Ultrashort gate-length pseudomorphic high-electron mobility transistors have been modeled using a full-band Cellular Monte Carlo simulator. The RF response and the cutoff frequency fT have been obtained for physical gate lengths ranging from 10 to 50 nm. These results, in turn, have been used in a transit-time analysis to determine the effective gate length in each case. By interpolation, one can make an estimate of the absolute upper limit for fT, which we find to be 2.9 THz in the device studied. Importantly, the effective gate lengths are considerably shorter than the depletion lengths. Thus, in general, any estimate of fT based on the latter quantity is likely too small by a quite significant amount.
AB - Ultrashort gate-length pseudomorphic high-electron mobility transistors have been modeled using a full-band Cellular Monte Carlo simulator. The RF response and the cutoff frequency fT have been obtained for physical gate lengths ranging from 10 to 50 nm. These results, in turn, have been used in a transit-time analysis to determine the effective gate length in each case. By interpolation, one can make an estimate of the absolute upper limit for fT, which we find to be 2.9 THz in the device studied. Importantly, the effective gate lengths are considerably shorter than the depletion lengths. Thus, in general, any estimate of fT based on the latter quantity is likely too small by a quite significant amount.
KW - Effective gate length
KW - Millimeter-wave transistors
KW - Monte Carlo methods
KW - Pseudomorphic high-electron mobility transistors (PHEMTs)
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U2 - 10.1109/LED.2008.918391
DO - 10.1109/LED.2008.918391
M3 - Article
AN - SCOPUS:41749122149
SN - 0741-3106
VL - 29
SP - 306
EP - 308
JO - IEEE Electron Device Letters
JF - IEEE Electron Device Letters
IS - 4
ER -