Design and simulation of a high temperature MEMS microhotplate for application in trace gas detection

In this paper, we present the simulation results of a high temperature MEMS micro-hotplate. The electro-thermomechanical behaviors of micro- hotplates (MHP) have been simulated using CoventorWare. In the simulation, the effects of various thicknesses of the silicon nitride (Si₃N₄) membrane layer on the temperature, mechanical deflection and power consumption of the MHP are evaluated. The effect of the addition of a layer of silicon carbide (SiC) on the MHP temperature distribution is also investigated. Results show that as the thickness of the Si₃N₄ membrane is increased from 0.3 μm to 3 μm, the power consumption of the MHP increases from 7.1mW to 34.3mW while the displacement of the membrane remains constant at a value of about 5.8 μm. It is also demonstrated that when the MHP is designed with a silicon carbide (SiC) heat distributing layer above the silicon oxide (SiO₂) insulating layer on top of the heater, the uniformity of the temperature on the MHP membrane is considerably improved as compared to a membrane without SiC. ©2008 IEEE.