A method of making a component for a microelectronic circuit and a semiconductor device and an optical waveguide made by that method.

摘要

A portion of a first layer (14; 34) exposed through an opening (20; 40) in a second layer (18; 38) is chemically converted to a compound having properties different to those of the first layer. By arranging that the conversion to the compound extends beyond the boundary of the opening and removing the compound, further material (24) can be depositied onto the substrate (12) through the opening (20). In this manner, a self-aligned semiconductor device can be formed with the further material (24) serving as the gate of the device. If the conversion to the compound is limited to the portion of the first layer directly below the opening (40) and the compound has an index of refraction different from that of the first layer, the converted portion (36) can serve as an optical waveguide.