Co-integration of optoelectronics and submicrometer CMOS

The rapid emergence of multichip modules (MCMs) and the continuing interest in wafer scale integration (WSI) provide important opportunities for successful insertion of high performance optical interconnections into real systems. The large area substrates and the distances between packaged wafer-level modules introduce distances of sufficient length that propagation of very high-speed digital signals along electrical lines will be difficult. At the same time, the substrates allow use of thin film technologies for fabrication of optoelectronic devices, optical waveguides, and other optical elements, drawing on the natural alignment accuracy of photolithographic definition of optical components to avoid several practical problems arising when optical elements are surface mounted. For such reasons, large area silicon wafers provide an important potential application for more aggressive use of optical interconnections. An important issue is growth of GaAs semiconductor regions within a silicon WSI or MCM substrate containing high performance silicon CMOS circuitry, seeking to co-integrate optical and silicon VLSI devices. Experimental studies of submicrometer CMOS device characteristics following thermal simulation of GaAs heteroepitaxial growth are summarized