Experimental cryogenic modeling and noise of SiGe HBTs
SiGe devices are an exciting contender for extremely low noise, cryogenically cooled amplifiers. This paper begins with a procedure for extracting a simple equivalent circuit model capable of accurately describing SiGe HBT devices. Next, small-signal modeling results obtained for a 3×0.12×18um^2 SiGe HBT at 15, 40, 77, 120, 200, and 300K are presented along with discussion of performance enhancements due to cooling of the device. Finally, the modeled noise performance is presented as a function of temperature and frequency using the concept of minimum cascaded noise temperature, a figure of merit which incorporates both noise temperature and gain.
Additional Information© 2008 IEEE. We appreciate the help of the Caltech Mixed Signal and RF Group, particularly, Prof. Ali Hajimiri, Aydin Babakhani, Florian Bohn, Hua Wang, and Yu-Jiu Wang for help with the IBM process. We thank Prof. David Rutledge and Glenn Jones for helpful discussions of the work, Hamdi Mani for help with assembly, and Ezra Long, Javier Bautista, and Jim Shell for measurement assistance. The tested devices were processed by IBM under the Trusted Foundry Program with sponsorship of Dr. K. Johnson of the US Naval Observatory. This work was supported by the Director's Fund of the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Agency.
Published - 04633202.pdf