The atomic structures of an incommensurate (001)/(110) Si grain boundary and 90° Si grain boundary were studied using transmission electron microscopy and refined by atomistic simulation (Stillinger-Weber potential). Samples were prepared by bonding one (001) Si wafer to one (110) Si wafer, and carefully orienting the 2 wafers so that they had a common [1¯10] direction. In the interfacial direction perpendicular to [1¯10], the [110]I direction of grain-I was parallel to the [001]II direction of grain-II. Because the ratio of these 2 vectors was √2, it was impossible for 2 integers, n and m, to exist such that n[110]I=m[001]II. The structure was thus incommensurate in this direction. The Z-contrast images obtained using a microscope equipped with a probe Cs-corrector clearly showed Si dumb-bells in the two grains, and permitted determination of the complex atomic structures of the interface. Near on-axis high-resolution transmission electron microscopic images were very useful for analysing the long-range order of the interface.

Structure of an Incommensurate 90° Si Grain Boundary Resolved with the Help of a Cs-Corrector for Illumination. J.L.Rouviere, F.Lançon, K.Rousseau, D.Caliste, P.H.Jouneau, F.Fournel: Journal of Physics - Conference Series, 2010, 209[1], 012041