Interstitial O profiles across epitaxial/Czochralski interfaces were studied by using high spatial resolution Fourier transform infra-red spectroscopy. Transmission measurements of a transverse wafer cross-section revealed an O contamination of the epilayer which was due to solid-state out-diffusion from the substrate during epilayer deposition. The O diffusivity values which were deduced from the experiments (table 186) suggested that the mechanism was hardly affected by the interface. The O contamination was strictly related to the type of dopant present in the substrate and not to that present in the epilayer. Such contamination of the epilayer, which was significant in n-type substrate samples, was suggested to explain the structural defects which were often observed in epitaxial layers.

M.Geddo, B.Pivac, A.Sassella, A.Stella, A.Borghesi, A.Maierna: Journal of Applied Physics, 1992, 72[9], 4313-20

Table 186

Diffusivity of O in Epitaxial/Czochralski Si Layers