Accurate and efficient analysis of the upward heat flow in InGaP/GaAs HBTs through an automated FEM-based tool and Design of Experiments

This paper presents an extensive analysis aimed at quantifying the impact of all the key technology parameters on the upward heat flow in state‐of‐the‐art InGaP/GaAs heterojunction bipolar transistors (HBTs) for various emitter areas and shapes. Extremely accurate thermal simulations are conducted in a relatively short time with a tool relying on a commercial 3‐D finite‐element method (FEM) solver and an in‐house routine for automated geometry construction, optimized mesh generation, sequential solution, and data storing/processing. Design of Experiments is used to define a thermal resistance model as a function of the aforementioned parameters on the basis of a few FEM data.