Sensitivity improvement of a dual axis thermal accelerometer with modified cavity structure

摘要

An improved dual axis thermal accelerometer is proposed in this paper. The thermal accelerometer consists of a centrally placed micro-heater, temperature detectors (placed symmetrically opposite of the heater) and silicon islands. A cavity is etched in silicon bulk to create thermal insulation between heater and the temperature detectors. The islands enhance the accelerometer sensitivity significantly. 3D structures of both types of accelerometers (with and without island) were designed and simulated in an FEM simulator. The results show that, the sensitivity of the accelerometer increases from 0.335 to 0.657 K/g by adding two pairs of silicon islands along two axes (where g is the gravitational acceleration i.e. 9.8 m/s(2) and K is the unit of temperature in Kelvin scale). The improvement of sensitivity is observed over a wide range of acceleration.