Patent ID: 8818146

Claim:
A method for fabricating a waveguide, comprising: placing a silicon substrate in a furnace; introducing steam into the furnace; raising a temperature inside the furnace to a first temperature level wherein a silicon dioxide layer is formed on a major surface of the silicon substrate; eliminating a moisture content in the silicon substrate by heating the silicon substrate at a second temperature level in an oxygen-rich environment; forming a first assembly by applying a photo-resist layer upon a portion of the major surface of the silicon dioxide layer; immersing the first assembly into a bath containing an etching solution selected for etching silicon dioxide; forming a second assembly by allowing the etching solution to act upon the silicon dioxide layer of the first assembly for a first period of time that is selected in order to: a) expose a portion of the silicon substrate, and b) form a wedge structure in the silicon dioxide layer; forming a third assembly by extending the first period of time by a second period of time in order to eliminate a foot region formed upon a sloping surface of the wedge structure; after eliminating the foot region, forming a fourth assembly by removing the photo-resist layer from the third assembly; and forming a waveguide component from the fourth assembly by exposing the fourth assembly to a xenon difluoride (XeF 2 ) environment that eliminates a portion of the silicon substrate and forms a support pillar below the wedge structure.