It is natural to assume that group V impurities diffuse in silicon by a vacancy mechanism, because they occupy substitutional sites. Based on the pair diffusion model that the impurities diffuse in silicon only via the diffusion of impurity-vacancy pair (E center), anomalous diffusions of phosphorus and arsenic can be explained.
On the other hand the relation between the enhancement of diffusion and the growth of extrinsic stacking fault during oxidation can be explained only on an interstitialcy mechanism.
Therefore it is the purpose of present note to introduce the recent studies of a vacancy and an interstitia silicon and to discuss the diffusion mechanisms of impurities. Even if the interstitialcy mechanism is correct, the impurities should diffuse likewise only via the diffusion of the pair of an interstitial silicon and an impurity. Therefore the atomistic model of this pair should be studied for the interstitialcy mechanism.
