基于氮化硅薄膜纳米孔制备及DNA分子检测

Fabrication of Si_3N_4 nanopore for DNA detection

通过对影响聚焦离子束溅射氮化硅纳米孔的溅射时间和离子束束流2个主要参数的研究,优化了聚焦离子束溅射纳米孔加工工艺.提出了利用聚焦离子束对氮化硅薄膜进行减薄后再溅射纳米孔的加工工艺.采用该加工工艺不仅可以减小纳米孔的直径和厚度,还可以减小纳米孔的锥度.最后利用氮化硅纳米孔研究了不同孔径的纳米孔对48 kbλ-DNA过孔姿态的影响,结果表明,孔径较大时,DNA分子过孔存在多种过孔姿态,孔径越小,DNA分子越容易被拉直过孔.同时针对DNA过孔时引起的阻塞电流,提出了简易的计算模型.

Main parameters affecting the structure of nanopore during focused ion beam（ FIB） sputtering silicon nitride membrane were studied： the sputtering time and the current of ion beam. Based on the optimizated FIB sputtering process,the FIB was used to reduce the thickness of the silicon nitride membrane firstly and then sputter the nanopore. This fabrication process could improve the structure of the nanopore,including the size and the cone of the nanopore. Finally,using the fabricated nanopore,the signature of 48 kb λ-DNA was studied when DNA molecules were translocated through Si3N4 nanopore. The result shows when the nanopore size the smaller,the DNA molecular is easily straight through the nanopore. Meanwhile a simple calculation model for the blocking current caused by DNA translocation is proposed.