自加热非晶锗热电阻MEMS流速传感器的制造与测试

Fabrication and Testing of MEMS Velocity Sensor Based on Self-Heating Amorphous Germanium Thermistors

摘要:

为扩大流速传感器的测量范围并降低功耗,制造并测试了一种基于自加热非晶锗薄膜热电阻的MEMS流速传感器,它是由嵌入氮化硅薄膜的四个非晶锗热敏电阻和一对环境测温补偿电阻组成。四个非晶锗热电阻同时作为自加热热源和测温元件,相互连接以形成惠斯通电桥。给出了MEMS工艺流程,微加工制造了尺寸为8.9mm×5.6mm×0.4mm的流速传感器芯片。搭建了低流速和高流速气流通道实验装置,对传感器的惠斯通电桥施加50μA的恒定电流(CCA),实现了0~50m/s范围内的流速测量。结果表明,传感器在低流速(0~2m/s)时的灵敏度约为81.6mV/(m/s),在高流速(2~50m/s)时的灵敏度约为51.9mV/(m/s),最大功耗仅约为1.03mW。

Abstract:

In order to expand the measuring range of flow sensor and reduce power consumption of the sensor, a MEMS flow sensor based on self-heating amorphous germanium film thermistors was fabricated and tested. It was composed of four amorphous germanium thermistors and a pair of environmental temperature measurement compensation thermistors, which were embedded in a silicon nitride film. The four amorphous germanium thermistors acted as self-heating heat sources and temperature measuring elements at the same time, and were connected with each other to form a Wheatstone bridge. The MEMS fabrication process was given, and the size of 8.9mm×5.6mm×0.4mm of the flow sensor chip was fabricated by micromachining. The low velocity and high velocity airflow pipeline experimental devices were built. With constant current (CCA) of 50μA supplied to the Wheatstone bridge of the flow sensor, the flow velocity measurement of 0~50m/s was realized by test. The results show that the sensitivity of the sensor is about 81.6mV/(m/s) when measuring 0~2m/s low flow velocity, and about 51.9mV/(m/s) when measuring 2~50m/s high flow velocity, and the maximum power consumption is only about 1.03mW.