The Laser‐Controlled Micrometer‐Scale Photoelectrochemical Etching of III–V Semiconductors

Laser‐controlled photoelectrochemical etching of III–V semiconductors using micrometer‐sized illumination regions has been investigated for varying laser parameters (power, spot size, wavelength) and etching solutions. The etching has been applied to a wide variety of semiconductor doping types. The micrometer spot size of the laser can induce higher etch rates for a given intensity when compared to broad illumination. In addition, the process has micrometer‐scale resolution and highly directional etch anisotropy. In this electroless process the laser etching rate is influenced by light‐induced voltage shifts in the surface potential. Finally, the dependence of the process resolution on carrier diffusion and etch depth is discussed.