Patent ID: 6773942
Filing Date: 2004-08-10
Classification: G02B

Abstract:
A method for fabricating an optical switch array comprising of the steps:providing a two side polished lightly doped (110) silicon substrate; forming a heavily doped layer with a same type impurity as the (110) silicon substrate on the back side of the (110) silicon substrate; growing a lightly doped epitaxial layer on the back side of the (110) silicon substrate; converting the heavily doped layer into a porous silicon layer by anodization in HF solution; forming a plurality of microchannels on the front side of the (110) silicon substrate so that each makes a 135 or 45 degree angle to a (111) crystal plane vertical to the surface of the (110) silicon substrate; converting the porous silicon layer into an oxidized porous silicon layer by thermal oxidization; forming electrical interconnections on the front side of the (110) silicon substrate; forming a plurality of (111) silicon planar plates each having two opposite sides made of (111) silicon crystal planes on the front side of the (110) silicon substrate by anisotropic etching; coating the two opposite surfaces of the (111) silicon planar plates with a reflection layer; removing the oxidized porous silicon by etching in a diluted HF solution to form a plurality of silicon stripes; filling said microchannels and the trenches formed in the etching process with photoresist; bonding a rigid plate to the (110) silicon substrate at the back side; and cutting the (110) silicon substrate by a dicing saw machine so that each (111) silicon planar plate and its supporting silicon strip are laterally separated from the (110) silicon substrate completely.