Samples of GaAs, which were encapsulated with thin films of amorphous Si at 450C, were annealed at temperatures of up to 1050C. The resultant poly-Si/GaAs interfaces were investigated by using secondary ion mass spectroscopy, Rutherford back-scattering spectrometry, and transmission electron microscopy. Little or no interdiffusion was detected at undoped Si/GaAs interfaces. The diffusion of dopants such P was detected. An enhanced diffusivity of P into GaAs was attributed to the diffusion of point defects which were created by the diffusion of As and Ga into the encapsulant. It was deduced that the P diffusivities in GaAs at doped polycrystalline Si interfaces were enhanced by factors of about 10000.

The Interdiffusion of Si, P, and In at Polysilicon/GaAs Interfaces. K.L.Kavanagh, C.W.Magee, J.Sheets, J.W.Meyer: Journal of Applied Physics, 1988, 64[4], 1845-54