Semiconductor microlenses fabricated by one-step wet etching

We fabricated refractive semiconductor microlenses using a diffusion-limited chemical etching technique based an Br₂ solution. The simple one-step wet etching process produced high-quality microlenses of GaAs and InP, the two most popular compound semiconductor materials used in optoelectronics. A spherical GaAs microlens with a nominal lens diameter of 30 μm exhibited a radius of curvature and focal length of 91 and 36 μm, respectively. The surface roughness, examined by atomic force microscopy (AFM), was measured to be below /spl plusmn/10 /spl Aring/. This microlens fabrication method should be readily applicable due to the simplicity in processing and the high-quality results.