Design of laser direct writing system for semiconductor photoelectrochemical etching

Semiconductor functional devices featuring intricate three dimensional(3D) micro-nanostructures are crucial for miniaturized devices. However, fabricating these structures non-destructively on semiconductors, known for their rigidity and brittleness, poses a significant challenge. To address this, we designed an electrochemical laser direct writing device in this study, combining the principles of semiconductor photoinduced corrosion with laser direct writing technology. A Gaussian beam is focused on a micro region on the surface of gallium arsenide (n-GaAs) through an electrochemical laser direct-writing system to induce the separation of electron-hole pairs. During this process, NO3- in the etching solution captures photogenerated electrons for the reduction reaction, while the surface of n-GaAs undergoes dissolution by oxidation due to the accumulation of holes. By precisely controlling the laser intensity during the scanning process, we successfully fabricated a predesigned 3D micro-nano structures on the surface of n-GaAs, demonstrating the feasibility of nanoscale machining accuracy.