@article { 4016626,
title = {Reconciliation of methods for estimating *f*_{max} for microwave heterojunction transistors},
journal = {IEEE Trans. Electron Devices (USA)},
volume = {38},
number = {8},
year = {1991},
note = {semiconductors;maximum frequency of oscillation estimation;microwave heterojunction transistors;HBTs;Mason's invariant gain;y-parameters;hybrid-π equivalent circuit;T-equivalent circuit;drift-diffusion equations;analytical expression;f_{T};effective base resistance;collector capacitance;transit-time effects;AlGaAs-GaAs;},
pages = {1685 - 92},
type = {article},
abstract = {An attempt is made to reconcile the various approaches that have recently been used to estimate the maximum frequency of oscillation *f*_{max} in high-performance AlGaAs/GaAs HBTs. *f*_{max} is computed numerically from the full expression for Mason's invariant gain using *y*-parameters derived from the different approaches, i.e., the hybrid-π equivalent circuit, the T-equivalent circuit, and the drift-diffusion equations. It is shown that the results for *f*_{max} are essentially the same, irrespective of the source of the *y*-parameters, provided that the phase delays due to transit of carriers across the base and the collector-base depletion region are properly accounted for. It is also shown, for the particular device studied, that the widely used analytical expression for *f*_{max}, involving *f*_{T} and effective base resistance and collector capacitance, is remarkably accurate for frequencies below those at which transit-time effects become important},
keywords = {aluminium compounds;equivalent circuits;gallium arsenide;heterojunction bipolar transistors;III-V semiconductors;semiconductor device models;solid-state microwave devices;},
URL = {http://dx.doi.org/10.1109/16.119002},
author = { Laser, A.P. and Pulfrey, D.L.}
}