Title :
Effect of reduced temperature on the f/sub T/ of AlGaAs/GaAs heterojunction bipolar transistors
Author :
Laskar, J. ; Hanson, A.W. ; Cunningham, B.T. ; Kolodzey, James ; Stillman, Gregory ; Prasad, Swamy J.
Author_Institution :
Illinois Univ., Urbana, IL, USA
fDate :
6/1/1991 12:00:00 AM
Abstract :
The high-frequency and DC performances of single-heterojunction Al/sub 0.25/Ga/sub 0.75/As/GaAs heterojunction bipolar transistors (HBTs) have been measured at temperatures between 300 and 110 K. It is found that the maximum unity-current-gain cutoff frequency increases from 26 GHz at 300 K to 34 GHz at 110 K. It is shown that electron diffusion as determined from the majority-carrier mobility does not accurately estimate the base transit time, at least until corrections for degeneracy and minority-carrier mobility enhancement are included. Reasonable agreement is obtained assuming that base transport is limited by the thermal velocity of electrons at reduced temperatures.<>
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; heterojunction bipolar transistors; semiconductor device models; solid-state microwave devices; 26 to 34 GHz; 300 to 110 K; Al/sub 0.25 /Ga/sub 0.75/As-GaAs; DC performances; HBTs; HF performance; base transit time; corrections for degeneracy; electron diffusion; heterojunction bipolar transistors; majority-carrier mobility; minority-carrier mobility enhancement; models; reduced temperature effect; semiconductors; single-heterojunction; temperatures; thermal velocity of electrons; unity-current-gain cutoff frequency; Cryogenics; Current measurement; Cutoff frequency; Gallium arsenide; Heterojunction bipolar transistors; Laboratories; Microwave measurements; Probes; Scattering parameters; Temperature dependence;
Journal_Title :
Electron Device Letters, IEEE
