We introduce Cu metal-organic chemical-vapor deposition as a potential means of conformal metal coating of the sidewalls of micromachined vertical mirrors. The optimal process temperature was experimentally found to be 215 °C, which gives high step coverage of better than 90%, and the surface roughness was less than 27 nm. The roughness, measured with an atomic force microscope, will induce a scattering loss less than 0.12 dB, which is small enough for vertical micromirror application. The experimental reflectances of Cu thin film were measured with a distributed-feedback laser (1550 nm) and found to be greater than 0.9 for incidence angles of 22.5° and 45°, and these reflectances were in good agreement with theoretical values.
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