The hierarchical hydrodynamic (HD) noise simulation model used in this work allows to generate a complete small-signal noise representation of the device under test. This new noise model based on full-band Monte-Carlo (MC) generated local noise sources in conjunction with transfer function fields is currently the most accurate Si/SiGe HBT noise simulation technique with tolerable CPU requirements. This new efficient numerical noise model is verified by full-band Monte-Carlo device simulations and compared to two well-known compact noise models, the thermodynamic and the SPICE model. (C) 2003 Elsevier B.V. All rights reserved.