Diffusion of Donor and Acceptor Elements in Silicon

The diffusion of the Group III (B, Al, Ga, In, and Tl) and Group V (P, As, Sb, and Bi) elements in silicon has been measured in the temperature range 1050–1350°C. A method based on change in conductivity through the penetration layer has been used for B and P. The p-n junction method has been used for the other elements. Aside from B and P, which have similar diffusional properties, the acceptor elements diffuse more rapidly than the donor elements. Diffusion coefficients are given by DB, P=10.5 exp − (85 000/RT), DA1=8.0 exp − (80 000/RT), DGa=3.6 exp − (81 000/RT), DIn, T1=16.5 exp − (90 000/RT), DAs=0.32 ×exp − (82 000/RT), DSb=5.6 exp − (91 000/RT), DBi=1030 exp − (107 000/RT) with an average estimated error of about ±40%. This corresponds to an error in the activation energies of about ±5 kcal. Sources of error including the effects of impurities in the oxides are discussed. D0 values in most cases conform to the predictions of Zener for substitutional diffusion.