A physics-based dynamic thermal impedance model for vertical bipolar transistors on SOI substrates

A physics-based compact model for the thermal impedance of vertical bipolar transistors, fabricated with full dielectric isolation, is presented. The model compares favorably to both three dimensional (3-D) ANSYS(R) transient simulations and measurements. Using the software package Thermal Impedance Pre-Processor (TIPP), a multiple-pole circuit can be fitted to the thermal impedance model. The thermal equivalent circuit is used in conjunction with a modified version of SPICE to give efficient electrothermal simulations in the dc and transient regimes.