Conventional Electron-beam lithography is done using a Scanning Electron Microscope (SEM), with a resolution limit of ~10 nm. However, there is continued need for higher resolution lithography. The goal of this project is to investigate higher resolution Electron-beam lithography using a Scanning Transmission Electron Microscope (STEM). In principle, the STEM has two main advantages: less scattering of incoming high energy electrons, and a smaller electron probe diameter. We have created 100nm wide trenches in PMMA resist, which are promising early results. Reducing the exposure of the resist will likely give higher resolution.
We have fabricated freestanding MnAs/GaAs nanowires using e-beam lithography and dry etching techniques. Nanowires as small as 75 nm in diameter were fabricated, with Magnetic Force Microscopy images of the nanowires showing the MnAs nanowire caps to be single-domain ferromagnets. The structures fabricated in this work hold promise for use in future studies of electrical spin transport.