The diffusion of P from a POCl3 source and into (111)-oriented n-type single crystals was studied by using sectioning via anodic oxidation, and 4-point resistivity techniques. The concentration profiles were fitted to a solution to Fick’s equation which involved a moving boundary that separated into 2 distinct phases. It was concluded that the surface region constituted a different phase to the remainder of the diffused layer. For short diffusion times, the phase boundary reaction was the rate-limiting process and the phase boundary moved at an almost constant rate. In the region beyond the phase boundary, P transport was controlled by 2 diffusing species; characterized by 2 appreciably different diffusion coefficients. The slow-diffusing component was present mainly in the transition region between the phase boundary and the fast-diffusion dominated region. The fast-diffusing component exhibited a maximum concentration at the phase boundary. The diffusivity at 820 to 1100C in the 2 cases could be described:

fast:     D (cm2/s) = 2.49 x 10-5 exp[-2.0(eV)/kT]

slow:     D (cm2/s) = 4.93 x 101 exp[-3.77(eV)/kT]

As the diffusion temperature was increased, the diffusion constants for slow and fast diffusion approached each other. At 1100C, the diffusion profile could be represented by a single diffusion constant.

J.C.C.Tsai: Proceedings of the IEEE, 1969, 57[9], 1499-506

The best linear fits to the solute diffusion data ([124] to [129], [133] to [144], [146] to [176], [188] to [192], [196] to [211], [215] to [223], [234] to [242], [252] to [283], [292] to [298], [306] to [314]) yield:

Al: Ln[Do] = 0.45E – 32.8 (R2 = 0.81); As: Ln[Do] = 0.29E – 23.2 (R2 = 0.87);

Au: Ln[Do] = 0.16E – 12.4 (R2 = 0.16); B: Ln[Do] = 0.29E – 22.6 (R2 = 0.79);

Cu: Ln[Do] = 0.22E (R2 = 0.86); Fe: Ln[Do] = 0.62E – 15.8 (R2 = 0.53);

Ga: Ln[Do] = 0.20E - 16.9 (R2 = 0.78); Ge: Ln[Do] = 0.29E – 23.2.8 (R2 = 0.98);

H: Ln[Do] = 0.17E - 9.9 (R2 = 0.07); Li: Ln[Do] = 0.25E – 9.6 (R2 = 0.48);

Ni: Ln[Do] = 0.29E - 19.4 (R2 = 0.66); O: Ln[Do] = 0.34E – 21.6 (R2 = 0.95);

P: Ln[Do] = 0.35E - 27 (R2 = 0.94); Sb: Ln[Do] = 0.35E – 29.3 (R2 = 0.96);

Si: Ln[Do] = 0.33E - 29 (R2 = 0.86)