We studied the diffusion of dopant impurities, that is, ion-implanted boron, phosphorous, arsenic, and antimony in SiO2 and determined the diffusivity of the impurities in SiO2 using secondary ion mass spectrometry and a process simulator. We also revealed anomalous diffusion of the dopant impurities in SiO2. (C) 1999 The Electrochemical Society. S0013-4651(98)09-005-3. All rights reserved.