Low Frequency Noise Characteristics of Self-Aligned AlGaAs/GaAs PowerHeterojunction Bipolar Transistors

摘要

The low frequency noise characteristics of modern self-aligned AlGaAs/GaAs powerHBT's have been studied as a function of bias, temperature, frequency, and circuit topology. The devices have a 1/f(sup gamma) behavior between 10 Hz and 100 Hz with 0.78 < or = gamma < or = 1.65. Strong deviation from 1/f(sup gamma) is measured at higher frequencies due to trapping. The bias dependence of the collector noise ranged from I (sub C)1.5-I(sub C)2.6, while that for the base noise ranges from I(sub B)0.7-I(sub B)2.5. In all cases the collector noise is greater than the base noise. The base noise is apparently dominated by surface recombination noise and generation-recombination (G-R) noise. The collector noise is due to recombination mechanism and G-R noise. The activation energy (Ea) of the most significant trap is approximately 0.58 eV. The noise of the devices tested was found to be dominated by material and fabrication related mechanisms and not by fundamental mechanisms. jg.