Fabrication of quantum semiconductor structures by high energy electron beam lithography of an inorganic epitaxial resist on GaAs

Abstract

Epitaxially grown calcium strontium fluoride on gallium arsenide has been patterned by high energy electron beam lithography and wet development. Fabrication of lines and dots of 8nm size is reported. Electron diffraction experiments indicate that fluorine is removed under electron bombardment with the formation of a calcium and strontium oxide. The end product of the radiolysis can be selectively etched in an acetic acid solution. A dose requirement of around 2×10 4C/cm 2 was necessary to form these features but a large dose latitude was observed. Possible applications of this epitaxial inorganic resist for the fabrication of quantum semiconductor structures are discussed.