IR and EPR Study of the Na Ion-Implanted SiO2/Si System

Abstract

Na ion-implanted silicon dioxide films are studied by infrared absorption (IR) and electron paramagnetic resonance (EPR) techniques. The samples were treated with sequential HF etchings, and subsequent IR and EPR measurements were made. The spectra are analyzed by principal component analysis (PCA), two-dimensional correlation analysis (2DCA), and effective medium analysis (EMA). The PCA and 2DCA show that a 1000 cm1 band appears in IR spectra in the silicon dioxide films after ion-implantation. And the 2DCA between IR and EPR spectra show that the 1000 cm−1 band is strongly correlated with the E' and/or peroxy radical in depth distribution; therefore, the band can be assigned to radical related Si-O stretching, such as O≡Si· and/or Si-O-O· configurations. The distribution of these configurations in the as-implanted film is also correlated to that of the voids. However, after annealing, the 1000 cm−1 band drastically diminished but the void volume fraction was unchanged and remained in the films. Annealing acted to reconstruct the dangling bonds to Si-O bonding and rearranged the void distribution in the film, but the volume fraction did not change drastically. The results of EMA support the depth distribution of the defects calculated from 2DCA.