Hitachi Ltd., Central Research Laboratory, 1-280 Higashi-koigakubo, Kokubunji, Tokyo, 185-8603.
Sci Rep. 2014 May 21;4:5000. doi: 10.1038/srep05000.
To date, solid-state nanopores have been fabricated primarily through a focused-electronic beam via TEM. For mass production, however, a TEM beam is not suitable and an alternative fabrication method is required. Recently, a simple method for fabricating solid-state nanopores was reported by Kwok, H. et al. and used to fabricate a nanopore (down to 2 nm in size) in a membrane via dielectric breakdown. In the present study, to fabricate smaller nanopores stably--specifically with a diameter of 1 to 2 nm (which is an essential size for identifying each nucleotide)--via dielectric breakdown, a technique called "multilevel pulse-voltage injection" (MPVI) is proposed and evaluated. MPVI can generate nanopores with diameters of sub-1 nm in a 10-nm-thick Si3N4 membrane with a probability of 90%. The generated nanopores can be widened to the desired size (as high as 3 nm in diameter) with sub-nanometre precision, and the mean effective thickness of the fabricated nanopores was 3.7 nm.
迄今为止，固态纳米孔主要通过 TEM 的聚焦电子束来制造。然而，对于大规模生产，TEM 束并不适用，需要一种替代的制造方法。最近，Kwok 等人报道了一种制造固态纳米孔的简单方法，并通过介电击穿在膜中制造了纳米孔（最小尺寸为 2nm）。在本研究中，为了通过介电击穿稳定地制造更小的纳米孔（特别是直径为 1 至 2nm 的纳米孔，这是识别每个核苷酸所必需的尺寸），提出并评估了一种称为“多级脉冲电压注入”（MPVI）的技术。MPVI 可以在 10nm 厚的 Si3N4 膜中以 90%的概率生成直径小于 1nm 的纳米孔。生成的纳米孔可以以亚纳米精度扩展到所需的尺寸（高达 3nm 直径），并且制造的纳米孔的平均有效厚度为 3.7nm。
