Polycrystalline Si was formed via the complete amorphization and subsequent thermal re-crystallization of the overlayer of Si-on-insulator substrates. The formation of the polycrystalline phase was confirmed via cross-sectional transmission electron microscopy, with the samples also being characterized by variable energy positron annihilation spectroscopy. By comparing the response of the variable energy positron annihilation spectra for samples in which polycrystal formation was confirmed, with samples in which the Si overlayer was re-grown as a single crystal, it was possible to observe the existence of vacancy-type defects at the film grain boundaries. For a sample with an overlayer of 1500nm thickness, a saturation of the measured Doppler-broadened S-parameter of 1.025 was estimated for the polycrystalline sample. This led to the conclusion that the majority of the vacancy defects at the grain boundaries were close in structure to that of the Si monovacancy.

Observation of Vacancy Defects at Silicon Grain Boundaries Formed Via Suppressed Solid Phase Epitaxy. K.J.Dudeck, W.D.Walters, A.P.Knights, P.G.Coleman: Journal of Physics D, 2008, 41[5], 055102 (7pp)