REACTIVE ION ETCHING OF SLOPED SIDEWALLS FOR SURFACE-EMITTING STRUCTURES USING A SHADOW MASK TECHNIQUE

A novel, very simple technique for the direct adjustment of the slope of facets in a reactive ion etching process is presented. The etching process is performed by screening the sample partially with an aluminu m shadow mask, which is located inside the dark space of the plasma. T he sidewall angle of etched lines, defined by a pattern mask on the sa mple, depends strongly on the distance between the shadow mask and the sample. The investigations are carried out with a methane-hydrogen pl asma. The angle of inclination of the sidewalls can be varied in a con trollable manner by more than 45 degrees. This technique is well suite d to fabricate 90 degrees reflectors, which are necessary for three-di mensional optical interconnects with planar waveguide structures. To a nalyze the optical quality of the etched mirror plane, the beam transf ormation was investigated by reflectivity measurements using a single aluminum-evaporated mirror structure, which is illuminated by a focuse d laser beam at a wavelength of 633 nm. (C) 1996 American Vacuum Socie ty.