Highly organised and dense vertical silicon nanowire arrays grown in porous alumina template on &lt;100&gt; silicon wafers

Therese Gorisse,Marc Zelsmann,Ludovic Dupré,Pascal Gentile,Mickael Martin,Denis Buttard

doi:10.1186/1556-276x-8-287

Abstract

In this work, nanoimprint lithography combined with standard anodization etching is used to make perfectly organised triangular arrays of vertical cylindrical alumina nanopores onto standard <100>−oriented silicon wafers. Both the pore diameter and the period of alumina porous array are well controlled and can be tuned: the periods vary from 80 to 460 nm, and the diameters vary from 15 nm to any required diameter. These porous thin layers are then successfully used as templates for the guided epitaxial growth of organised mono-crystalline silicon nanowire arrays in a chemical vapour deposition chamber. We report the densities of silicon nanowires up to 9 × 109 cm−2 organised in highly regular arrays with excellent diameter distribution. All process steps are demonstrated on surfaces up to 2 × 2 cm2. Specific emphasis was made to select techniques compatible with microelectronic fabrication standards, adaptable to large surface samples and with a reasonable cost. Achievements made in the quality of the porous alumina array, therefore on the silicon nanowire array, widen the number of potential applications for this technology, such as optical detectors or biological sensors.

Highlights

Low-cost and versatile fabrication of functional nanostructures, for example for nanowires, nanocrystals or nanotubes, becomes of great importance in an increasing number of potential commercial devices [1,2,3,4,5,6]
Another promising directed self-assembly (DSA) approach is the use of anodic aluminium oxide (AAO) as templates for the growth of
We present our results on the use of NILguided AAO templates for the fabrication of highly regular and dense epitaxial silicon nanowire arrays grown perpendicularly to silicon substrates and on surfaces as large as 4 cm2

Summary

Introduction

Low-cost and versatile fabrication of functional nanostructures, for example for nanowires, nanocrystals or nanotubes, becomes of great importance in an increasing number of potential commercial devices [1,2,3,4,5,6]. The most common DSA approach consists of organising di-block copolymer features [7] in lithographically created topographical [8] or chemical [9] templates Another promising DSA approach is the use of anodic aluminium oxide (AAO) as templates for the growth of this material is a good candidate for the fabrication of organic, inorganic or metallic nanostructures [13,14]. Until now, very few references report the use of AAO for the growth of these nanoobjects, and it is the conventional methods to produce AAO, so-called simple or double anodization [10,15], which have been employed [4,16] With this technique, the hexagonal order is maintained only on domains of few square micrometres, a sacrificial layer of aluminium is lost and the pore’s size and shape distribution is high [17]. These limitations lead obviously to a reduction in the performance of later devices or a decrease in the number of potential applications [18]

Methods

Results

Conclusion