A New Structure for CMOS Thermal-Bubble-Based Accelerometer

In this paper, we design and fabrication a novel thermal-bubble-based micromachined accelerometer with advantages of minimum solid thermal conductance and high sensitivity successfully. It can detect two-dimension acceleration changed and apply to technology of inclinometers, anemometers and flow meters. A new accelerometer consists of a micro heater and two pairs of thermopiles floating over an etched cavity that is constructed by our proposed micro-link structure. The heater and the thermopiles are connected by network-like structure of micro-links, which enhance the structure and greatly reduce the solid heat flow from the heater to the hot junctions of thermopiles. The samples are fabricated by TSMC 0.35μm 2P4M CMOS process which is provided by CIC with outstanding strong structures and uniform quality. Our design is proved to be adequate for commercial batch production. We measure the output signal by inclining the sensor to evaluate the performance of this accelerometer. The measurement shows the output signal is inverse proportional to the tilt angel and the output voltage is increased when the input power increases. Furthermore, the sensitivity was obtained for acceleration vs. output voltage with an average slope of 0.325μV/g in this case.