OBLIQUE SHADOW DEPOSITION TECHNIQUE FOR ALTERING THE PROFILE OF GRATING RELIEF PATTERNS ON SURFACES

An oblique shadow deposition technique for altering the profile of grating relief patterns on surfaces is described. The technique essentially represents a method whereby a series of grating masks may be superimposed in precise registration with each other. By appropriate choice of deposition angle, deep grooves may be generated from shallow profiles, rounded or sinusoidal profiles may be transformed to structures with planar vertical walls, and symmetric profiles may be made asymmetric. In conjunction with ion-beam milling, the technique has been used to increase the depth of fine period gratings on GaAs and to produce grooves ∼4000 Å deep on the surface of YAG, 10 times deeper than could be obtained by ion-beam milling of photoresist.