Vertical optical communication through stacked silicon wafers using hybrid monolithic thin film InGaAsP emitters and detectors

The authors report the first demonstration of vertical optical communication through stacked Si wafers using low-cost hybrid monolithic thin-film InGaAsP/InP emitters and detectors, designed for operation at 1.3 mu m. A thin-film InGaAsP homojunction light-emitting diode (LED) (4.5- mu m thick) was deposited onto a polished, nitride-coated Si wafer using a modified epitaxial liftoff technique. A InP/InGaAsP/InP p-i-n photodetector (4.5- mu m thick) was similarly deposited on an identically prepared Si wafer. The emitter and detector were then aligned, resulting in a stacked wafer configuration suitable for vertical through-wafer optical communication. This integration technique eliminates the need for direct growth of compound semiconductors onto Si.<>