| High field asymmetric ion mobility spectrometry(FAIMS)technology is based on the ion mobility spectrometer(IMS),on the basis of using ion in high and low electric field ion migration rate of different preparation,has small volume,high sensitivity,good stability as well as the advantages of short response time.With 40 years’ development,the environmental safety inspection,chemical warfare agents and explosives detection fields form broad application prospects.At present,many foreign schools and units have done a lot of researches based on FAIMS technology and some companies have realized the productization of FAIMS instruments.Meanwhile,the domestic researches in the field related to FAIMS technology are relatively backward;In view of the wide application prospect of FAIMS and the research status of FAIMS in China,a parallel FAIMS gas sensor is designed and fabricated in this paperFor parallel FAIMS sensor,its structure mainly includes three parts:ionization region,migration region and collection region.In the ionization region,the ultraviolet lamp ionization source is selected as the ionization source in this paper by comparing the differences among different ionization sources.The mobility characteristics of ions in high and low electric fields are explored,and the influences of ion diffusion,Coulomb force,ion recombination and other factors on the movement of ions in the migration zone are analyzed,simplifying the movement model of ions in the migration zone.According to Paschen’s law and plate deformation theory,the specific dimensions of plates in the migration zone and the collection zone are designed,and their rationality are verified.In terms of sensor preparation,a complete process flow is designed based on MEMS micromachining technology,and the corresponding mask is drawn.The key structures were prepared by lithography,etching,magnetron sputtering,stripping and anodic bonding.In the sensor’s test,the characterization of the chip’s surface morphology was tested first by field emission scanning electron microscope and laser microscopy.Then a ptfe material assembly was designed which assembled the air inlet ionization,uv lamp and FAIMS chip to a carrier.Finally a simple test system was set up and pressure condition of sensor response in different gas environment was tested under normal temperature and pressure.The test results show that the sensor’s response time is 5s and recovery time is 8s in 200ppm isobutylene.In the meanwhile,the sensor also showed a good response in acetone,which is expected to be applied to the detection of exhaled gas in diabetic patients in the future. |
