Fabrication Of Three-Dimensional Stacked Silicon Nanosheet Biosensors

Silicon nanowire field effect biosensors are one of the most promising devices for future applications in rapid in situ detection due to their high sensitivity,ease of operation and compatibility with CMOS processes.But silicon nanowire and other field-effect biosensors are faced with the problem of strong Debye screening effect,which severely limits their development.In this paper,we designed and fabricated a three-dimensional stacked silicon nanosheets structure to overcome the Debye screening effect and achieve direct DNA detection in high ionic strength solution.The main research contents and achievements of this paper are as follows:1.A three-dimensional stacked nanosheet structure is proposed to overcome the Debye screening effect by using the advantage of spatial structure.COMSOL simulation results show that the three-dimensional stacked structure obtains a1990-fold enhancement of current response compared with the planar structure of silicon nanowires,which theoretically proves the advantage that the structure can effectively overcome the Debye screening effect and improve the detection sensitivity.2.Based on the GAA perimeter gate process,a three-layer stacked structure with a 5 nm cavity was designed and fabricated using a "top-to-down" approach,and the electrical performance characterization showed that the device achieved a switching ratio of >106 and good on-chip uniformity.3.The device was used for DNA sensing and detection,and the results showed that for 12-base DNA detection,a current response >10% higher than that of the silicon nanowire FET biosensor was obtained,and a minimum detection limit of 1a M was obtained.The advantages of the 3D stacked structure for biosensing detection are demonstrated...