A micromachined, shadow-mask technology for the OMVPE fabrication of integrated optical structures

A micromachined, silicon shadow-mask technology is described which extends the capabilities of shadow-masked OMVPE for the fabrication of nonplanar mi cro-optical elements. The deep reactive ion etched (DRIE) shadow mask is in expensive, reusable and produces smooth, nonplanar structures with precise control of position, shape and size. Direct fusion bonding of the mask to t he substrate was found to be a reliable and reproducible method for attachi ng the mask to the substrate during growth. The DRIE shadow mask technology allows the deposition of microlenses with focal lengths out to 3 mm withou t the central flattening that was previously observed in shadow masked lens es grown under the epitaxial mask. We also describe novel applications of t his technology in the fabrication of micromirrors and concentrically-variab le Bragg reflectors, which should improve mode discrimination in large aper ture VCSELs.