Nanostructural and Optical Features of the Tb-doped Si-rich SiO2 Thin Films Prepared by Magnetron Sputter Techniques

초록

Visible photoluminescence (PL) of Si-rich SiO2 (SRSO) has attracted much attention due to the potential application of these materials in optoelectronic devices. Quantum confinement effects and surface state models have been proposed to interpret the visible PL phenomena at room temperature. However, the origin of the luminescence as well as the way of controlling the PL spectra features have been controversial issues. In addition, very little experimental reports have been published on the SRSO films, in particular, doped with Tb3+. In order to control the optical features of the Tb-doped SRSO films, it is indispensable to acquire tuning techniques of the films’ chemical characteristics. In addition, the overall variation of their nanostructural and optical features with sputter conditions should be understood. In this study, RF magnetron sputter techniques were used to prepare SRSO thin films on silicon wafers. A cylindrical pure SiO2 target, parallelepiped Si and Tb chips were utilized as main as well as auxiliary sputter targets, respectively; the SiO2 target, Si and Tb chips were 2″5 mm and 550.5 mm in size, respectively; 16 pieces of Si chips and various numbers of Tb chips were placed on top of a SiO2 main target for simultaneous sputtering of Si, Tb and SiO2. Post-deposition heat-treatments were carried out at 600℃ for 30 min in nitrogen atmosphere. We investigated the nanostructural and chemical characteristics of the Tb-doped SRSO films as a function of deposition parameters and post-deposition heat-treatment conditions.