Nanofabrication for quantum devices

Abstract

Fabrication of structures for investigation of quantum effects frequently involves the use of MBE/CVD type growth processes to achieve control on an atomic scale in vertical direction and a wide range of combinations of lithography and pattern transfer techniques for control in lateral directions. The challenges ahead lie in the degree of lateral control with which the lithography can be performed, i.e. resolution and placement accuracy, but also in the throughput of the lithography equipment once technological applications are considered. Electron beam resolution can certainly extend to the 1 nm regime, in the case of the STM even to 0.1 nm, appropriate resist materials have to be found, however. Parallelism may be introduced into nanolithography through contact printing with X-rays, electron, ion, or X-ray projection, or arrays of miniaturized scanning electron or ion columns. Pattern transfer relies on a broad spectrum of subtractive and additive processes ranging from wet and dry etching to selective growth techniques. Pattern fidelity and damage to the material are the key issues. © 1992 IOP Publishing Ltd.