The effect of O upon the diffusion of Na implanted into Si was studied for the first time from 500 to 850C. High-resistivity p-Si (ρ > 1kΩcm) grown by using the Czochralski method in a magnetic field (mCz) with an O concentration of 〜3 x 1017/cm3 was used. For comparison, Si grown by using the crucible-less float-zone method was used. The temperature dependences of the effective diffusion coefficient of Na in the mCz-Si and float-zone Si crystals (figure 9) were described by:

D (cm2/s) = 1.12 x 100exp[−1.64(eV)/kT]

and

D (cm2/s) = 2.4 x 10-2 exp[−1.29(eV)/kT]

respectively. It was assumed that the larger values of the diffusion parameters for O-containing Si were caused by the formation of complex aggregates that contained Na and O atoms.

Diffusion of Implanted Sodium in Oxygen-Containing Silicon. V.M.Korol, S.A.Vedenyapin, A.V.Zastavnoĭ, V.Ovchinnikov: Semiconductors, 2008, 42[9], 1122-6

Figure 9

Diffusion of Na in Si

(Open circles: O-containing Si; filled circles: float-zone Si)