High C-doped base InGaP/GaAs HBTs with improved characteristics grown by MOCVD

The improvement in the emitter-base leakage current of HBTs has been investigated by the use of an InGaP emitter. InGaP/GaAs n-p-n HBT structures with high C-doped bases, grown by MOCVD, have been fabricated and these devices show Gummel plots with near ideal I-V characteristics (n_c=1.00 and n_b=1.09). Measured current gain remains relatively flat over five decades of collector current and its magnitude is greater than unity at collector current as low as 0.1 mu A. The characteristics of these HBTs were compared with fabricated AlGaAs/GaAs HBTs having similar device structure. The superior performance of the InGaP emitter HBT is demonstrated.