Paper PS-FrM10
Combination of Bio-template and Ultimate Top-down Etching Processes for Defect-free, High Density, Size-controlled and Excellent Uniform Si-Nanostructure for Ideal Quantum Effect Devices

Friday, November 13, 2009, 11:20 am, Room B2

Nanometer-scale structures such as quantum dots (QDs) have been widely studied because they have potential applications to the development of quantum effect devices, such as single electron transistors, quantum dot lasers and quantum dot solar cells. To realize quantum dots, the fabrication of defect-free, size-controlled and uniform sub-10-nm-scale structures is needed. However, it is difficult for conventional optical lithography and plasma etching processes to satisfy these requirements.

In this study, we proposed a novel nanofabrication process for the fabrication of nanostructures, which combines a biomaterial template, radical etching and neutral beam etching (NBE). We fabricated silicon nanodisks (disk-shaped silicon nanostructures with diameters of about 10 nm on a very thin silicon oxide film) by using a ferritin iron core as etching mask and Cl NBE. Additionally, we succeeded in precisely controlling the nanodisk diameter by using surface treatment of NF₃ gas + hydrogen radicals (NF₃ treatment). The surface oxide thickness and its removal conditions greatly affected the fabricated nanodisk diameter. It was notable that the coulomb staircases of nanodisk structures were obtained with a conducting AFM probe at room temperature. The successful fabrication of Si nanodisk should be attributed to the defect-free etching process that involved our neutral beam. Our new process is very useful to fabricate defect-free and size-controlled nanostructure for ideal quantum effect devices.