Analytical modeling method of thermal spreading resistance in BAW filters

Abstract

As the power requirements in BAW filters steadily increase, thermal behaviour emerges as a key asset to ensure device performance and reliability. Under these conditions, self-heating mechanisms drive to possible situations where the filters no longer meet the electrical specifications. In addition to that, the evaluation of the heat spreading might help to define the resonators and pillars distribution along with the overall performance of current BAW filters. In the past, numerical methods based on FEM have been used to study the temperature distribution under high-power (HP) signals, lacking efficiency in terms of computational time. The motivation of this work is to describe an analytical method that is able to simulate very fast, without the need of costly FEM simulation, the heat spreading in a filter according to the spatial distribution of the resonators.