片上加热电容式湿度传感器研究

提出了一种集成加热结构的电容式湿度传感器结构。对传感器的稳态加热特性进行了分析,并利用红外线热成像技术对传感器加热过程以及稳态温度响应进行了研究。在5 V电压信号的加热下,传感器温度上升约30℃,且温度分布均匀,传感器敏感区域温差<4℃。在加热与不加热条件下,分别对传感器的湿度敏感特性与响应时间特性进行了测试。不加热时,传感器的灵敏度为0.00913 pF/%rH,回滞≈0.12 pF,响应时间约120.8 s；以5 V脉冲信号加热后,传感器灵敏度为0.00903 pF/%rH,最大回滞≈0.025 pF,响应时间约75.2 s。加热后传感器性能有了显著提高。

Study of a Capacitive Humidity Sensor with an on-chip heater

Heating characteristics of a capacitive humidity sensorwas studied. Simulation was carried out toanalysis the Steady state temperature distributions in the sensor. Theinfrared thermal imaging technologywas used to verify the sim-ulation result of the FEM model. The results showed that the temperaturesin the sensor were increased about 30 ℃with a heating signal of 5 V,and the variations of temperature in different locations wereless than 4℃ in the sensing area. Tests with heating and un-heating were both carried outfor comparison. Without heating,the sensitivity of the sensor was 0.009 13 pF/%RH,the hysteresis was 0.12 pF,and the response time was about 120.8 s;with a 5 V pulse heating signal,the sensitivity was 0. 009 03 pF/%RH, the hysteresis was improved to 0. 025 pF and response time wasimproved to 75.2 s. By comparison,it could be seen that the performance of the sensor was improved by heating.