Novell type of highly photosensitive germanium doped silica glass: Co-doping with nitrogen

A novell type of highly photosensitive germanosilicates has been developed. By adding ammonia to the gas mixture of silane, germane and nitrous oxide in the plasma enhanced chemical vapor deposition process, nitrogen has been incorporated in the glass matrix forming germania/silica oxynitrides. UV-induced refractive index increases greater than 3-10(-3) has been measured without any hydrogen loading. Besides the highly increased photosensitivity the nitrogen doped germanosilicates exhibit excellent mechanical properties. Dependant on the deposition and annealing parameters the glass can be deposited to have zero stress when deposited on silicon. Further more can stable glasses with up to 30 mole % germania be deposited when nitrogen in incorporated.