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The development of monolithically integrated optoelectronics in silicon has been hindered to date primarily because of silicon's inefficient optical emission properties. Recently, however, nanostructured systems exploiting quantum confinement effects have shown the potential to circumvent this problem. In this study, silicon-rich silicon oxide (SiOx, x<2) thin films doped with erbium have been deposited on silicon substrates by electron cyclotron resonance plasma enhanced chemical vapour deposition (ECR-PECVD). The formation of silicon nanoclusters along with optically active erbium ion complexes during high temperature annealing results in strong erbium photoluminescence near a wavelength of 1.54 μm. A portion of the deposition parameter space for the ECR-PECVD system has been mapped in an attempt to optimize the films for this luminescence. The resulting films ranged in composition from 0% to 22% excess silicon and 0.45% to 3.7% erbium, as determined by Rutherford Backscattering Spectroscopy. The effects of annealing were investigated between 600 oC and 1000 oC under flowing nitrogen gas. The 1.54μm emission was found to be enhanced by the presence of excess silicon, reaching a maximum at ~5-8 atomic % excess and an 800 oC anneal. This result strongly suggests the sensitization of infrared, erbium luminescence by silicon nanoclusters. The films exhibited an additional blueviolet light emission which has also been attributed to the erbium dopant. The visible and infrared luminescence signals were found to occur in inverse proportion to each other with the visible signal decreasing as the amount of silicon excess increases.
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