Nanometer-scale Pattern Transfer Using Ion Implantation
- PDF / 446,232 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 106 Downloads / 240 Views
H8.3.1
Nanometer-scale Pattern Transfer Using Ion Implantation Naomi Matsuura, Todd W. Simpson1, Chris P. McNorgan1, Ian V. Mitchell1, Xiang-Yang Mei, Patrick Morales and Harry E. Ruda Center for Advanced Nanotechnology, Department of Materials Science and Engineering, University of Toronto, 170 College St., Toronto, Ontario, M5S 3E3, Canada. 1 Department of Physics and Astronomy, University of Western Ontario, London, Ontario, N6A 3K7, Canada. ABSTRACT Conventional, broad-area, ion implantation has been combined with unconventional masking to create 2-D geometrical patterns of amorphization in single crystals, with selectable motifs. The patterns are fully developed by use of selective etching. Two examples are discussed. In the first example, a self-assembled array (with lattice spacing ~1 µm) of silica spheres is used as an implant mask over InP. The variation of the mask thickness created by the sphere geometry modulates the implantation depth in a periodic fashion, which is subsequently revealed after selective etching of the associated amorphized volumes. In the second example, nanochannel arrays in an alumina film are used as an implant mask to produce a hexagonal closed packed array of amorphized cylinders in InP and SrTiO3 substrates. The ion beam-amorphized regions of the substrate are then removed by selective chemical etching to achieve the full 3-D patterning of 55 nm diameter holes on a 100 nm lattice spacing. INTRODUCTION One of the continuing challenges of nanometer-scale pattern production is the fabrication of large-area patterns with high flexibility and yield, and at a low cost. Patterning methods using self-assembly phenomena provide efficient and low-cost alternative approaches to conventional lithographic techniques for realizing ordered nanostructures. However, the self-assembly approach is typically material dependent, and as such, cannot be easily transferred to other material systems. In contrast, conventional ion implantation allows direct patterning in a wide range of ion-substrate systems, but requires specialized masks for nanoscale patterning. Broadarea ion implantation through self-assembled masks appears to offer a route that overcomes both the material dependence of self-assembly and the difficulty and expense of fabricating nanoscale masks. In this work, two different types of self-assembled, hexagonal masks are used: a self-assembled close-packed SiO2 microsphere array (lattice spacing ~1 µm) and a self-assembled nano-channel alumina (NCA) array (lattice spacing ~100 nm). Heavy ions are implanted through the masks to selectively introduce damage into the substrate. The damaged areas are then removed through the use of a wet etchant selective to the amorphized volumes, and the resultant profiles are imaged by field emission scanning electron microscopy (SEM) to determine the fidelity of the nanoscale pattern transfer. Selective etching provides both a method to pattern the substrate and a method to study the 3-D damage distribution produced by the implant. This nano-scale pattern
Data Loading...
