Electron-paramagnetic-resonance study of silver-induced defects in silicon

In this paper two electron-paramagnetic-resonance spectra are reported in silicon doped with silver in a water vapor atmosphere. These centers, labeled Si-NL56 and Si-NL57, show the orthorhombic-I and trigonal symmetries, respectively, and an effective electron spin S=1/2. Based on studies with enriched silver isotopes and analysis of the observed twofold hyperfine splitting, the participation of one silver atom is established for both centers. The Si-NL56 center is identified as an isolated substitutional silver atom. Due to the presence of an additional hyperfine interaction with a nuclear spin I=5/2, the Si-NL57 spectrum is assigned to a complex of silver with another impurity introduced during the diffusion process. Taking into account the sample preparation procedure, the Si-NL57 center is attributed to an Al-s-Ag-i pair in a negative charge state.