The use of ion beam damage to locally suppress photoelectrochemical etching of GaAs has been previously described. This study examines the limitations on the resolution of patterns formed by this technique, using a focused ion beam. Directly written patterns of damage were formed in Si‐doped n+ GaAs (1×1018 cm−3) by implantation with a 120 keV focused beam of Ga ions. Photoelectrochemical etching of the substrate was suppressed, not only in the implanted regions themselves, but also within a region extending a few micrometers beyond the implanted region. This suppression distance limits the smallest pattern feature or resolution achievable with this technique. The resolution was examined as a function of incident laser intensity, implant dose, the dimensions of the damaged areas, and distance between the damaged areas. A simple one‐dimensional model suggests that the diffusion of the photogenerated carriers, relative to their reaction rate at the surface, determines the resolution achievable.The use of ion beam damage to locally suppress photoelectrochemical etching of GaAs has been previously described. This study examines the limitations on the resolution of patterns formed by this technique, using a focused ion beam. Directly written patterns of damage were formed in Si‐doped n+ GaAs (1×1018 cm−3) by implantation with a 120 keV focused beam of Ga ions. Photoelectrochemical etching of the substrate was suppressed, not only in the implanted regions themselves, but also within a region extending a few micrometers beyond the implanted region. This suppression distance limits the smallest pattern feature or resolution achievable with this technique. The resolution was examined as a function of incident laser intensity, implant dose, the dimensions of the damaged areas, and distance between the damaged areas. A simple one‐dimensional model suggests that the diffusion of the photogenerated carriers, relative to their reaction rate at the surface, determines the resolution achievable.
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