针对射频识别(RFID)与无线传感器网络(WSNs)融合研究的需要,基于0.35μm CMOS工艺设计了一种集成加速度传感器。传感器单元采用从单晶硅衬底的背面进行深反应离子刻蚀工艺,背面刻蚀完成后再正面对金属和介质复合层进行各向异性刻蚀。集成电容式传感器接口电路基于锁相环原理,将传感器信号转移到频率域处理,避免了高功耗的A/D转换器的使用,直接完成电容/数字转换。后期测试结果显示:所设计的集成加速度传感器线性度好,稳定性高,功耗低,适合无源RFID及其它超低功耗应用设计。
Aiming at requirement of integration study of radio frequency identification( RFID) and wireless sensor networks( WSNs) technology,an integrated acceleration sensor is designed based on 0. 35 μm CMOS process.Sensor unit utilizes deep reactive ion etching procedure on the backside of the monocrystalline silicon substrate,and then employs anisotropic etching on the front side of the metal and dielectric composite layer. The sensor interface circuit is based on phase-locked loop theory,converts sensor signal to frequency domain avoid usage of ADC which has very high power consumption and achieves capacitance to digital conversion directly. The measurement results prove that the proposed acceleration sensor achieves high performance on linearity,stability and power consumption,which is especially suitable for application on passive RFID and other ultra-low power consumption field.