Research On Preparation And Application Of Solid-sate Nanopores Based On Bulk Micromachining Technology

Sensing platforms based on solid-state nanopores have had important applications and made significant progress in several research fields,such as biosensing,molecular sequencing,seawater desalination and other fields.Solid-state nanopores,as its core part,are widely concerned by scholers and researchers.With the proliferation of nanopores demand,large-scale nanopores fabrication technology using inexpensive means has become a hot research topic.In this paper,the technical scheme for arrayed preparation of solid-state nanopores is thoroughly investigated in response to the above demand,and the preparation scheme is further improved to meet the cost and efficiency in harmony with increasing the controllability of preparation.Among the current common nanopore preparation technologies,the wet etching method has the unique advantages of low cost,high throughput,flexibility and tunability.In this paper,the mechanism and the method of anisotropic wet etching to form nanopores are firstly explored.The time-controlled equations of the etching process and the limiting size of nanopores are obtained by establishing macroscopic and microscopic models,respectively.In order to improve the controllability of the preparation process,an ion current feedback mechanism is introduced at the key step of opening to monitor the opening event.Nanopores with characteristic sizes of 50.7 nm,13.4 nm,8.3 nm,and 3.2 nm were successfully fabricated on single-crystal silicon substrates using the above ion currentassisted wet etching method.Then the inhomogeneous phenomena of the etching process were analyzed,and it was found that the lithography precision error and wet etching error were the main causes of the inhomogeneous phenomena.To further shrink the feature size of nanopores,the atomic layer deposition technology is used to process the prefabricated nanopore arrays,and the nanopores with larger feature sizes are successfully shrunk to sub-20 nm or even completely closed.By analyzing the relationship between the deposited film thickness and the shrinkage size of the nanopores,it is found that the shrinkage rate was related to the film deposition rate by a factor of 2.In addition,this paper investigated the application of nanostencil lithography.The nanopore array chip prepared by the above method was used as a template to deposit and shape a three-dimensional boss structure with an average planar feature size of 339 nm on the substrate.By observing and analyzing the size and height of the bumps,it is found that the shape and size of the bumps are uniform.Therefore,the nanohole array prepared in this paper has the application potential of high-precision nanostencil lithography.