A novel micromachined sensor-head for optical data storage applications

We report on a novel micromachined sensor head for optical data storage devices. The head is based on a 6 x 6 aperture array with subwavelength dimensions. In comparison to previously introduced flat-aperture heads, a tip based array is presented which profits from a recently presented reliable fabrication process of apertures in the 100 nm regime and below. This fabrication process exploits inhomogeneous thickness distributions and modified etching rates of thermally generated siliconoxides on (001)-oriented silicon wafers at relatively low temperatures, and makes it possible to open apertures with dimensions below 150 nm in hollow SiO2 pyramidal shaped tips. A metallization process is finally used to provide optical opacity and to further reduce the overall aperture dimensions to less than 100 nm. The fabrication process of these sensors is described in detail and the results are confirmed by SEM photographs.