Fabrication of a porous alumina mask on the large surface area of a semi-insulating semiconductor substrate

Abstract

We describe a method for fabricating a large-scale homogeneous porous alumina membrane as a mask for dry etching of the large surface area (of the order of one square centimeter) of a semi-insulating semiconductor substrate. It employs direct anodization of the aluminum layer deposited on the substrate, which is simple, therefore, suitable for high-throughput productions. However, the process with a non-conductive semiconductor substrate suffers from the issues of quality control of the pores caused by nonuniform current flow in the aluminum layer in the anodization process. Hence, we have implemented a new fitting to the anode that provides uniform current flow into the aluminum layer, which allows us to fabricate highly homogeneous nanopores on the large-scale alumina membrane.