Localized suspended micro-heater structure using dry etching for sensing and actuation application

Abstract

In this paper, we present the results of a study encompassing design, simulation and fabrication of suspended meander micro-structure, which will form the basis of different types of sensors in various applications such as vacuum gauge, mass flow sensor, and thermal accelerometer. In this research we compare the released approach of suspended structure and unreleased approach of design of micro-heater to provide guidance to optimize and choose the fabrication approach for localized heating or substrate heating. The finite element modeling carried out using COMSOL Multiphysics predicts electrical and thermal behavior of Joules heating effect in the stationery and time-dependent study with the tolerance of <8 %. The material selected in the fabrication process was LPCVD silicon nitride which can provide high thermal stability and high mechanical strength. The device is fabricated using a dry etching technique with very few steps. Further by characterizing these devices, we demonstrate experimentally that the suspended microstructure with released approach is able to heat upto the temperature of 440 °C at the power consumption of only 36 mW with the response time of only about 1 ms. This “fully released” miniaturized meander structure without any intermittent support leads to fast response, high sensitivity and low power consumption.