Silver diffusion into Si (1 1 1) substrate at moderate temperatures (400-700 degreesC) has been studied by the use of secondary ion mass spectrometry (SIMS), Rutherford backscattering spectrometry (RBS), and optical etch pit observations. The diffusion coefficient of silver has been estimated. Silicon crystallographic defects start to form at the silicon surface when the annealing temperature is above 450 degreesC. This phenomenon is related to the silver diffusion. The activation energy of the defect formation is approximately 2.46 +/- 0.26 eV. It is higher than the reported activation energy (1.59 eV) for silver diffusion at higher temperature (1100-1300 degreesC). The possible mechanisms are discussed to account for the experimental results. (C) 2002 Elsevier Science B.V. All rights reserved.