Thermo-Electro-Mechanical Simulation of Semiconductor Metal Oxide Gas Sensors

TLDR

The semiconductor industry seeks to integrate many functions into a single portable device, and while CMOS-compatible sensor fabrication has enabled this, sensors still need calibration and optimization, especially because microheaters consume most power to heat the sensing film for operation. The study aims to model and simulate semiconductor metal oxide gas sensors to facilitate their integration, recognizing that such modeling is essential to avoid costly laboratory experimentation. The authors employ finite element method (FEM) models, including a Cauer network electro‑thermal model, to simulate the thermo‑electro‑mechanical behavior of the sensors, enabling design calibration for low power and reliability. The simpler Cauer electro‑thermal model accurately reproduces experimental observations, demonstrating its efficiency.

Abstract

There is a growing demand in the semiconductor industry to integrate many functionalities on a single portable device. The integration of sensor fabrication with the mature CMOS technology has made this level of integration a reality. However, sensors still require calibration and optimization before full integration. For this, modeling and simulation is essential, since attempting new, innovative designs in a laboratory requires a long time and expensive tests. In this manuscript we address aspects for the modeling and simulation of semiconductor metal oxide gas sensors, devices which have the highest potential for integration because of their CMOS-friendly fabrication capability and low operating power. We analyze recent advancements using FEM models to simulate the thermo-electro-mechanical behavior of the sensors. These simulations are essentials to calibrate the design choices and ensure low operating power and improve reliability. The primary consumer of power is a microheater which is essential to heat the sensing film to appropriately high temperatures in order to initiate the sensing mechanism. Electro-thermal models to simulate its operation are presented here, using FEM and the Cauer network model. We show that the simpler Cauer model, which uses an electrical circuit to model the thermo-electrical behavior, can efficiently reproduce experimental observations.