Improved compact modeling of output conductance and cutoff frequency of bipolar transistors

2001 ◽  
Vol 36 (9) ◽  
pp. 1390-1398 ◽  
Author(s):  
J.C.J. Paasschens ◽  
W.J. Kloosterman ◽  
R.J. Havens ◽  
H.C. de Graaff
Keyword(s):  
Cutoff Frequency ◽  
Bipolar Transistors ◽  
Compact Modeling ◽  
Output Conductance

scholarly journals Study on Possible Double Peaks in Cutoff Frequency Characteristics of AlGaAs/GaAs HBTs by Energy Transport Simulation

VLSI Design ◽  
1998 ◽  
Vol 8 (1-4) ◽  
pp. 437-442
Author(s):  
T. Okada ◽  
K. Horio
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Energy Transport ◽  
Transport Model ◽  
Cutoff Frequency ◽  
Bipolar Transistors ◽  
Electron Velocity ◽  
Collector Current ◽  
Double Peak ◽  
Double Peaks ◽  
Energy Profiles

By using an energy transport model, we simulate cutoff frequency fT  versus collector current density IC characteristics of npn−n AlGaAs/GaAs heterojunction bipolar transistors (HBTs) with various n−-collector thickness and n−-doping densities. It is found that the calculated fT  characteristics show double peak behavior when the n−- layer is thick enough and the n−-doping is high enough to allow existence of neutral n−- region. The mechanism of the double peak behavior is discussed by studying energy band diagrams, electron-energy profiles and electron-velocity profiles. Particularly, we discuss the origin of the second peak (at higher IC) which is not usually reported experimentally.

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