We have recently developed dedicated software in order to simulate the ray propagation phenomena as associated with 1µm x 1µm Si LED’s (450-750nm emisson) when integrated in silicon 0.35 and 1.2 micron CMOS integrated circuitry. These simulations are extremely valuable for studying optical propagation mechanisms of the Si LED generated light longitudinally along CMOS structures, as well as optimizing the emission of light out of these structures. Coupling of light into adjacently positioned micro-optical structures is also feasible. The technology enables development of a wide variety of on-chip optically-mechanically based sensors (MOEMS) for measuring temperature, vibration, optical index and optical absorption changes. These sensors can be miniaturized and integrated with great cost and operational efficiency, either in hybrid or monolithic form in CMOS integrated circuitry. 

Using the tool, structures could be generated that increase the light emission level from the Silicon substrate to the environment from 0.01 to 0.21. Furthermore, dedicated optocoupler structures could be designed that can increase the coupling factor from Si LEDs from the silicon substrate to dedicated Silicon Nitride overlayers by 0.016 to 0.13.  

It has also been established, that the Silicon CMOS nitride passivation overlayer offer exceptional good waveguiding properties above 650nm, for which wavelengths these layers are basically transparent. This forms the basis for further advanced waveguide development.   

The work forms the basis of the following South Africa Patent Applications which have currently international coverage: 2009/05249, 2009/04665, 2009/04666, 2009/04162, 2009/00632, 2008/1089.