Monolithic integration of microphotonics with CMOS microelectronics using molecularly engineered materials and nanostructures

Many approaches have been attempted to integrate the capabilities of traditional CMOS microelectronics with photonic devices. The majority of these approaches have recently involved photonic devices fabricated from unique materials, silicon in the case of CMOS microelectronics. Most other work has concentrated on assembly and packaging schemes for hybrid integration of microelectronics and microphotonics. These capitalize neither on the economies of production of the CMOS microelectronic industry nor the capability of photonics to provide unique capabilities as demonstrated in the long haul telecom industry. Work to find silicon based solutions have produced interesting results but significant opportunities exist for materials and processes that would permit microphotonic fabrication on any CMOS. Microphotonic-microelectronic monolithic integration with current materials, manufacturing processes, and packaging/assembly prove difficult. However, it is noted that CMOS process flows may well undergo significant alteration to adopt new, and often less robust materials, such as polymer dielectrics, in the near future, to achieve device performance goals. The materials will cause traditional CMOS fabrication process flows to be modified to accommodate the less robust organics and nanocomposites. A silicon nanocomposite with variable in plane index of refraction (VIPIRtrade) and a poled plasma polymer that produces a stable nonlinear electro-optic material at room temperature are used for device fabrication. The poled polymer is used to "tune" the resonant wavelength of the ring resonators to provide routing, modulating, wavelength agility, and MUX/DEMUX functions. Materials are molecularly engineered to produce long term stability. The microring resonator is fabricated using a VIPIR nanocomposite and overcoated with the NLO poled polymer. This paper will describe not only the material synthesis but the process specifics and flow required to fabricate the photonic structure on the CMOS known good die. After the passive photonic structure was fabricated, a stable poled plasma polymer was deposited to control microring resonator tuning. The input of the buffer was driven through a simple test program directly from a personal computer parallel port. Electrical input and output of the buffer were monitored. The eight wavelengths that corresponded to the eight channels of the buffer, in the 1550nm band, were multiplexed and fiber coupled to the light input bus on the device. The octal buffer still functions electrically while multiplexed optical transmission is now incorporated. We report the operation characteristics of both the electronic and photonic functions of the device