Noise modeling of Si and SiGe devices

Efficient and accurate noise modeling is discussed for Si and SiGe devices. By comparison with measurements for short-channel MOSFETs and Monte Carlo simulations it is shown that the hydrodynamic model yields reliable results for noise. In the case of ultra-short gate devices it is found that the drain excess noise factor increases only moderately with decreasing gate length in contrast to some previous publications. In the case of SiGe HBTs it is shown that the noise at medium frequencies can be described by shot noise due to the base and collector currents and thermal noise due to the base resistance. This seems to be due to the rather low base resistance of modern SiGe HBTs.