Low frequency noise characteristics of self-aligned AlGaAs/GaAs power heterojunction bipolar transistors

A comparison of low-frequency noise characteristics and noise sources in NPN and PNP InP-based heterojunction bipolar transistors

“…This model was applied to explain the low-frequency noise characteristics of BJTs [1], [13]. Tutt et al [3] proposed a model based on the previous one, but used a Tee configuration. Both models are shown in Fig.…”

“…2(b) with in position A. However, Tutt et al [3] proposed that may flow through part of the base resistance in HBTs, and therefore it is more appropriate to have it connected in position B. and can be obtained based on the Tee-model with connected in position A (assuming is negligible)…”

“…The diffusion process in the bulk material and the recombination process in the base surface have been reported as sources of noise [1], [2]. The traps existing in devices have also been identified as sources of generation-recombination (G-R) noise [3]. The diffusion noise due to mobility fluctuation represents a fundamental limit to noise.…”

“…The low-frequency noise characteristics of HBTs have been reported for different material systems. Tutt et al [3] reported that the low-frequency noise of AlGaAs/GaAs power HBTs was limited by technology rather than the fundamental diffusion noise mechanism. D. Costa et al [2] concluded that fluctuations in the extrinsic-base surface recombination velocity are the origin of the noise in small-geometry AlGaAs/GaAs HBTs.…”

Investigation of HBT oscillator noise through 1/f noise and noise upconversion studies

“…Npn GaAs/AlGaAs I-IBT's often do not display perfect l/f noise spectra. It is known that a substantial noise bulge is seen in the l / f iioise spectra [5] in the vicinity of lOkHz due to trapping. This is often associated with the n-type doping of the AlGaAs in the emitter and was present in the spectrum of the transistor tested here.…”