A Scalable Mextram Model for Advanced Bipolar Circuit Design

Abstract

In this thesis, a referenced based scaling approach and its parameter extraction for the bipolar transistor model Mextram is proposed. It is mainly based on the physical properties of the Mextram parameters, which scale with the junction temperature and geometry of the bipolar transistor. The scalable electrical parameter in the scaling rules is normalized to a reference parameter at reference temperature and geometry. The scalable model is implemented in AHDL Verilog-A language, which can be used in many commercial simulators. Along with the scalable model, a unified extraction procedure for temperature and geometry parameters of the scalable model has been implemented in an IC-CAP model file using an example of high-speed SiGe HBT technology as a case study. The essential feature of the extraction methodology is a direct extraction of the temperature and geometry parameters from the measured electrical characteristics. The electrical model parameters as the reference parameters are extracted only once for a single reference temperature and geometry. No additional tool for temperature and geometry parameter extraction is needed. As a result, the accuracy is improved and the scalable model library generation time is greatly reduced.