Nanostructures, in particular nanowires, have recently obtained a lot of attention and may play a significant role in the miniaturization and improvement of novel electronic and computing devices. As an example, semiconductor III-V nanowires provide a significant potential to create a new generation of lasers and on-chip coherent light sources due to their ability to operate as single mode optical waveguides, resonantly recirculate optical fields and provide gain.
However, the manufacturing of nanostructures, such as nanowires on semiconductor substrates is challenging due to their small dimensions and the high degree of accuracy that is needed to meet the often very narrow parameter specifications. Many nanostructure applications require the fabrication of apertures with a dimension in the range of 100 nm or significantly less in thick dielectric layers. Sometimes, a large array of such apertures with carefully defined dimensions and at precisely defined positions need to be fabricated on a semiconductor substrate. The challenges in fabricating such aperture patterns result mainly from the selection of proper resist layers with high selectivity in pattern transfer during etching processes. There are not many appropriate resist layers that withstand etching of very deep apertures, and the resist is oftentimes more easily etched than the desired dielectric layer underneath. There is a need for a manufacturing technique that allows to manufacture ultrathin aperturers in thick dielectric layers easily and swiftly and with a high degree of accuracy.