Based On The Design And Study Of The Chemical-sensitive Field-effect Sensor

ChemFET is an active device using chemical field effect to control the conductivity of solid materials. Because of its small size and high sensitivity, it has received a wide range of application in signal detection of microorganism.First, a chemical polarization sensor based on silicon with simple processing methods was assembled. Its stability was tested, and the change of onstate current before and after assembling of the molecular membrane around was compared. Results showed that the device has certaim of rectifier, and the onstate current increases with the increasing of molecules chains. Disrupted by poor experimental environment and machining technique, the stability of its current signal was not very good, so, it must be further improved.On the basis of the previous work, this paper is designed and producted integrate different specifications FET chips being sensitive to chemical polarizatio with micro-electronics technology. The influence of organic molecules structure on the on-resistance of chips has been researched. And we achieved satisfactory results of research and experimentation through experimental verification.Using molecular self-assembly and molecular recognition technology, different molecular structure of the film on the chip was assembled. The effect of organic molecule structure with different carbon chain length on the on-resistance of chip was also studied. Current-voltage(I-V) curves of onstate characteristics of chips were measured after assembly of different membrane of molecular structure in chips. Assembling different long chain saturated acids, alkylamine and aliphatic alcohol can decrease the onstate resistance of the chips with the increasing of molecular chains, and increase its onstate characteristics. However, it would effect the onstate resistance of chips when assembled different long chain saturated acid salts and alkylamine salts. When the molecular membranes have the same molecular structure but different of the end of substituents, molecular membrane skeleton was the benzene ring. The resistance of the onstate of chips would decrease with decreasing electronegative of the end of substituents. On the contrary, it would increase with decreasing electronegative of the end of substituents when assembly the molecular membrane which have the same of 1'3-Butadiene structure but different of the end of substituents.