Bimetallic-catalyst metal-assisted chemical etching for tailored formation of high-aspect-ratio III−V compound semiconductor submicron pillar arrays

High-aspect-ratio micro- and nanostructures play a pivotal role across diverse technological domains, encompassing microelectronics processors, photovoltaic devices, and optoelectronics. The conventional methods of fabricating these structures often involve reactive-ion dry-etch processes utilizing ionized gases or wet chemical-based etching. Recently, the emergence of metal-assisted chemical etching (MacEtch) has showcased significant potential in enabling the creation of nanoscale features with exceptionally high aspect ratios. Nonetheless, the application of MacEtch to quaternary III−V and heteroepitaxial semiconductors remains relatively unexplored. This research introduces a novel approach named inverse-progression metal-assisted chemical etching (I-MacEtch) that centers around the utilization of a bimetallic catalyst, specifically focusing on the utilization of a bimetallic catalyst. This technique is employed to fabricate well-organized arrays of submicron pillars. The study elucidates that precise control over the vertical and lateral etch rate can be attained through the selection of a suitable metal adhesion layer, which improves the overall catalyst work function, thereby facilitating the streamlined fabrication of ordered arrays of InP submicron pillars possessing predefined aspect ratios.