Germanium silicon oxynitride high index films for planar waveguides

摘要

A composition represented by the formula Si1-xGexO2(1-y)N1.33y, wherein x is from about 0.05 to about 0.6 and y is from about 0.14 to about 0.74 exhibits properties highly suited for use in fabricating waveguides for liquid crystal based optical devices. In particular, the compositions have an index of refraction of from about 1.6 to about 1.8 for light at a wavelength of 1550 nm, and/or a coefficient of thermal expansion of from about 2.5x10-6° C.-1 to about 5.0x10-6° C. -1. The compositions also have inherently low hydrogen content, and a high hydrogen permeability which allows better hydrogen removal by thermal annealing to provide a material which exhibits low optical losses and better etching properties than alternative materials.