STRUCTURE AND METHOD FOR FORMING A LIGHT DETECTING DIODE AND A LIGHT EMITTING DIODE ON A SILICON-ON-INSULATOR WAFER BACKSIDE

A structure and method for fabricating a light emitting diode and a light detecting diode on a silicon-on-insulator (SOI) wafer is provided. Specifically, the structure and method involves forming a light emitting diode and light detecting diode on the SOI wafer's backside and utilizing a deep trench formed in the wafer as an alignment marker. The alignment marker can be detected by x-ray diffraction, reflectivity, or diffraction grating techniques. Moreover, the alignment marker can be utilized to pattern openings and perform ion implantation to create p-n junctions for the light emitting diode and light detecting diode. By utilizing the SOI wafer's backside, the structure and method increases the number of light emitting diodes and light detecting diodes that can be formed on a SOI wafer, enables an increase in overall device density for an integrated circuit, and reduces attenuation of light signals being emitted and detected by the diodes.