DocumentCode :
3448017
Title :
Distributed high frequency effects in bipolar transistors
Author :
Versleijen, M.P.J.G.
Author_Institution :
Philips Res. Lab., Eindhoven, Netherlands
fYear :
1991
fDate :
9-10 Sep 1991
Firstpage :
85
Lastpage :
88
Abstract :
The origin of distributed high-frequency effects in bipolar transistors is reviewed. The occurrence of these distributed effects as a function of frequency is related to the approach of characteristic frequencies, fT and fac for vertical and lateral effects, respectively. It was shown that a hybrid-π AC model provided with a transcapacitance between base and collector correctly predicts the phase of the transadmittance up to fT. The transcapacitance value naturally follows from a physical large-signal charge model and incorporates neutral base and base-collector depletion region delay. AC crowding in the internal base can be effectively modeled by adding a capacitor in parallel to the intrinsic base resistance. The capacitance value is related to the total input capacitance at the base. A critical emitter width which makes it possible to determine when AC crowding dominates vertical NQS (non-quasi-static) effects is defined. It is shown that when the model for the intrinsic transistor is properly extended with parasitic elements, as has been done in the MEXTRAM model, HF small-signal transistor behavior can be correctly simulated up to the highest frequencies of practical interest
Keywords :
bipolar transistors; semiconductor device models; AC crowding; HF small-signal transistor behavior; MEXTRAM model; base-collector depletion region delay; bipolar transistors; critical emitter width; distributed HF effects; high frequency effects; hybrid- pi AC model; large-signal charge model; neutral base; transadmittance; transcapacitance; Bipolar transistors; Capacitance; Circuit simulation; Circuit testing; Degradation; Delay effects; Equations; Frequency; Laboratories; Voltage control;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Bipolar Circuits and Technology Meeting, 1991., Proceedings of the 1991
Conference_Location :
Minneapolis, MN
Print_ISBN :
0-7803-0103-X
Type :
conf
DOI :
10.1109/BIPOL.1991.160962
Filename :
160962
Link To Document :
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