Research On Cantilever Beam Array Pulse Sensor Based On MEMS Technology

In this paper, based on MEMS technology, the pulse sensors based on cantilever beam array were designed and fabricated on <100> orientation high resistivity monocrystalline silicon chips with double-sided polishing. This structure was made up of three cantilever beams(B1, B2, B3), masses(m1, m2, m3) at the top of the cantilever beam and twelve diffusion resistances(R1 ~ R12) at the root of the three cantilever structures, four diffusion resistors make up the wheatstone bridge structure, there were three bridges. Based on piezoresistive effect and elastic element analysis, when the applied force F?0 N, cantilever beams deformation lead to change of diffusion resistors,and the applied force was tested by changing the output voltage of the Wheatstone bridge. The size of cantilever beam structure was studied to konw the influence of the characteristic. Based on the above, sensor chip layout was designde by L-Edit integrated circuit layout desingn software. The pulse sensors based on cantilever beam arraychip were fabricated by micro electromechanical system technology, and using inner bonding pressure welding technology on printed circuit board to complete encapsulation.By using the scan signal generator(SINO CERA YE1311), shaking table(Molal Shaker JZK-2), Agilent oscilloscope, Level gauge(Nano Map 500LS), digital multimeter(Agilent 34410A), Stepper motor lifting platform(RKD507-A) and the other instruments to test the dynamic characteristics and corresponding force sensitive characteristic of pulse sensor. The experiment results show that, when the applied voltage was VDD=1.0 V, piezoresistors length-width ratio of 80 ?m/20 ?m, the resonance frequency of the pulse sensor based on cantilever beam array were 3.019 k Hz, 3.121 k Hz, 2.900 k Hz. When the applied voltage was VDD=5.0 V, output voltage for 100 mg full scale were 111.08 m V, 116.2 m V and 115.95 m V, the sensitivity were 0.54 m V/mg,the linearity were 4.28 %F.S., 4.43 %F.S. and 4.80 %F.S., the repeatability were2.18 %F.S., 1.52 %F.S. and 0.59 %F.S., the hysteresis were 2.39 %F.S., 1.58 %F.S. and0.97 %F.S., the accurency were 5.90 %F.S., 5.23 %F.S. and 4.98 %F.S..The experiment results indicate that, the designed and fabricated the pulse sensorsbased on cantilever beam array in this paper can achieve the measure of pulse force,they also have high sensitivity,the accuracy of the pulse will improve through cantilever beam array, which lays a further foundation for improving the performance of the pulse sensor.