Diffusion and Solubility of Gold Implanted in Silicon

Diffusion and solubility of gold implanted in ≪100≫ p-type silicon have been investigated by Rutherford Backscattering Spectrometry and spreading resistance techniques. The gold concentration profiles are U-shaped and the concentration at the middle of the wafer thickness (C
^s
m
) is proportional to the square root of the diffusion time in agreement with the kick-out mechanism. The diffusion coefficient D*
I
(see text) is well described by D*
I
= 7.0* 10
^-3
exp(-1.61/kT) cm
²
sec in the temnperature range 1173-1373 K. The entropy factor associated to the ionization of the gold donor level has been determined to be 28±2.