It was recalled that, in the case of B diffusion, the value of the sheet resistance that was observed on plain check slices was almost always appreciably smaller than the sheet resistance that was deduced from diffused resistors. The actual value of the discrepancy depended upon the size of the window and the surrounding masking oxide geometry. These facts were further important factors in the 2-dimensional simulation of diffusion processes. The results were presented here of a series of experiments which involved the use of multi-layered mask structures that consisted of a thermal oxide, Si3N4, and SiO2. On the basis of the results, it was suggested that most of the observations could be explained with the help of a theoretical model that was based upon the surface diffusion of B over Si and SiO2. The model assumed a high solubility of B in the oxide, and a high surface diffusion coefficient. Numerical calculations demonstrated that the model could explain most experimental observations.

S.A.Abbasi, F.Rahman: Journal of the Electrochemical Society, 1995, 142[11], 3928-32