The migration of Zn was studied by using angle-lapping and stain-etching techniques. It was found that the Zn diffusion depth was proportional to the square root of the diffusion time, and depended upon the composition of In1-xGaxP. That is, the effective diffusion coefficient at a given diffusion temperature decreased according to:

D(cm2/s) = 3.935 x 10-8 exp[-6.84x]

while the activation energy increased according to:

Q(eV) = 1.28 + 2.38x

This was attributed to a decreasing contribution from interstitial diffusion with increasing Ga content.

S.T.Kim, D.C.Moon: Japanese Journal of Applied Physics, 1990, 29[4], 627-9