Advances in low temperature processing of silicon nitride based dielectrics and their applications in surface passivation and integrated optical devices
The passivation of silicon by low temperature processed dielectrics, particularly SiN, has recently received a great deal of attention for applications in photovoltaics technology. Low surface recombination velocity is a key issue for ongoing improvements of a large variety of silicon based microelectronic devices. This review discusses the various deposition techniques and also gives recent results of nitride passivation. Issues such as the impact of deposition parameters, thermal stability, interface traps and surface recombination velocity measurements are described. The benefits achieved by the passivation process on the photovoltaic device performance are also discussed. The potential of silicon oxynitride, a gradient index material, for the fabrication of integrated optical devices has been presented. Advances in the growth of SiON for application to integrated optics have been summarized. Based on optimized SiON technology the review reports on special purpose wave-guiding structures such as microcavity resonators, electrooptic modulators, polarization splitters and second harmonic generation devices. SiON technology offers a silicon-compatible technology, a waveguiding structure with high dielectric-index contrast, a low optical loss <0.15 dB cm-1, in the 1550 nm telecommunication window and a negligible polarization dependence.