Fabrication And Detection Of Dual-gate Field Effect Transistors(DGFETs)

Objective:Malignant tumors are one of the major threats to human health today Early diagnosis and timely treatment can significantly improve the quality of life and five-year survival rate of patients after surgery.Therefore,as an important indicator of early tumor,high sensitivity,real-time,accurate detection to tumor markers is of great significancein the early diagnosis of cancer.In the past decade,silicon nanowire sensors have attracted widespread attention in the detection of proteins,viruses,and nucleic acids.Compared with the traditional detection methods,silicon nanowire sensors have the advantages of simple operation,short time consumption,no radiation and low consumables.In this study,based on the previous studies,we further optimize the previous single-gate device processing process,adopte a dual-gate structure and silicon nanoribbons(SiNR)structure with a larger surface area,in order to achieve a high sensitivity detection to tumor markers.Method:In this study,by the Nikon 112 lithography combined with RIE etching method,the preparation of a high sensitivity dual-gate silicon FET biosensor based on nanoribbon is conducted.The source electrode,drain electrode,surface gate,top gate,silicon nanoribbon and passivation layer are distributed on the surface of the sensor The introduction of double gates and silicon nanoribbon enhance the control ability of the field effect transistor,and improve the detection sensitivity and stability of the sensor.In the modification process,we used the classical APTES-Glu covalent modification method to form a strong binding between inorganic nanodevices and organic antibody proteins through a series of covalent bonds.In order to verify the effect of the modification,we choose the fluorescent protein as the target protein,and the modification results are observed under the fluorescence microscope after the modification.Finally,the same modification method was applied to modify the CEA antibody to the detection area of nanoribbon.Then detect the carcinoembryonic antigen(CEA)with this sensor,in order to evaluate the detection performance of the new device and compare with the previous single-gate sensor.Result:We have successfully obtained new nanoribbon devices by the new processing technology.The introduction of double gates and nanoribbon structure makes the performance of the device significantly improvedConclusion:A new type of dual-gate controlled silicon nanodevices made by Nikon 112 lithography combined with RIE etching method is produced in this study.It has superior structure and properties.Experiments show that the new device can meet the needs of various tumor markers with high specificity,high sensitivity and instant detection,and it has wide application prospects in clinical detection.