Photoluminescence from Er-doped Si-rich Si oxides deposited by magnetron sputtering in Ar or $Ar+H2$ plasmas

The authors have studied photoluminescence (PL) from Er-doped Si-rich Si oxide (SRSO) films deposited by magnetron sputtering of an $Er+Si+SiO2$ composite target in Ar or $Ar+H2$ ambients. When the samples were annealed in $N2$⁠, for the film grown in an Ar ambient, the PL annealing behaviors reveal that the emissions from the film are defect-related and that the $Er3+$ PL at $1.54μm$ is possibly triggered by a defect-mediated energy transfer process; while for the films grown in an $Ar+H2$ ambient, the emissions from the SRSO matrix are suppressed and the Er PL intensities increase significantly but differently dependent on the $Ar:H2$ ratios during sputtering. After annealing the samples in an $Ar+5%H2$ (FG) ambient, however, almost no Er PL was observed from the film grown in the Ar ambient, while the Er PL intensities of the films grown in the $Ar+H2$ ambient increase further compared to those annealed in $N2$⁠. Fourier transform infrared spectroscopy shows that the absorption of the samples after FG annealing is weaker than after annealing in $N2$⁠. The PL properties have also been compared to those of a sample grown by plasma enhanced chemical vapor deposition. The roles of hydrogen during sputtering and postdeposition annealing are discussed.