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+Si O2 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 1.54 μm 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.