A Study On Uncooled Infrared Detector Based On Film Bulk Acoustic Resonator

Infrared?IR?detector is a kind of optical sensor,which responds to the external infrared radiation and will convert it to other physical signal output.The IR detector has a great value when applied in a verity of fields,such as military,medical,industrial.Uncooled IR detector can work at room temperature and has the advantages of small size,cheap price and low power consumption,which contribute to its universal attention and rapid development.Based on the popular research topic,this thesis applies microelectromechanical system technology to infrared detection,and proposes an uncooled infrared detector based on film bulk acoustic resonator?FBAR?.For the first time these two test methods are combined in an IR detector,which has a lower limit of detection and a wider application.The main achievements of this thesis can be summarized as follows:1.Using FBAR as the infrared detector,the fabrication process and the infrared test system are simply introduced.The two test methods wire bonding and probe are compared and the performance of the device is analyzed.2.For the resonant test method,the sensing mechanism of frequency shift caused by the infrared is proved by experiment and simulation methods.The temperature-frequency coefficient is tested to be TCF=-28 ppm/?C and the results of detecting IR,which are analyzed and processed,are NEP=40 nW/Hz^1/2,D*=3.5×10⁵ cm·Hz^1/2/W,NETD=16 mK,respectively.Besides,the single and array of IR detector are studied through FEM simulation method.The thermal characteristics and temperature propagation characteristics are analyzed separately.3.For the resistive test method,firstly the effect of temperature on the impedance variation of parallel resonance frequency is eliminated by experiment.Then the MBVD equivalent circuit model simulation and electrical characteristic test are used to obtain the conclusion that the impedance of parallel resonance frequency will change when infrared is applied.Finally,the results of infrared detect test are analyzed and processed to gain the value NEP=0.89 nW/Hz^1/2,D*=1.59×10⁷cm·Hz^1/2/W,which are two orders of magnitude higher than those obtained of resonant mode.