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We report on the investigation of the structural, chemical and optical properties of undoped and Eu-doped SiOC thin films synthetized by RF magnetron sputtering. Undoped SiOC exhibits an intense room temperature luminescence at ~ 500 nm, and an important contribution to this signal is due to the presence of Si-C bonds. Moreover, when inserted in a SiOC matrix, Eu ions have a higher solid solubility with respect to pure SiO2; as a consequence, we observe a reduction of Eu clustering phenomena. Furthermore the reducing properties of SiOC, related to the presence of C, allow the prevalence of the Eu2+ emission over the Eu3+ one. Through the control of the annealing conditions it is possible to obtain an intense light emission at 440 nm. These properties propose SiOC as a novel and efficient Si-based host matrix for Eu and open the way to promising perspectives of Eu-based materials for photonic applications and LED fabrication.

Fluorine is known to strongly influence the dopant diffusion and electrical activation in Si. Similar effects might be exploited in Ge for optimizing its application in microelectronics. The role of F on the electrical activation of As in Ge after thermal treatments is elucidated. We have found that F, enriching the Ge matrix with vacancies strongly affects the electrical response of As-doped junctions. We also demonstrated that the F-interstitials clusters, formed next to the end-of-range region, have an acceptor-like behavior. These phenomena are characterized by chemical and electrical profiling analyses and by positron annihilation lifetime spectrometry.

We studied the influence of energy and fluence of a F+implantation on the end-of-range (EOR) defects and on B activation in Ge+-preamorphized Si. After F+co-implantation at either 10 or 22keV, B transient-enhanced diffusion as well as B electrical deactivation are both reduced. In contrast, 10keVF+implantation does not affect the EOR evolution, while defects are stabilized after 22keVF+implantation. Our results, therefore, show that the beneficial effects related to F+co-implantation cannot be explained in terms of a stabilization of the EOR defects.