Origin of subboundary formation in encapsulated recrystallized Si films on SiO sub 2.

We have made extensive microdiffraction studies of the crystallographic orientation of recrystallized (001) Si films, and transmission electron microscopy (TEM) analysis of dislocations at the initiation sites of the subboundaries. The microdiffraction studies reveal a characteristic folding behavior between the subgrains with an increasing tilt angle in the direction away from the initiation sites. The TEM results show straight dislocations along the [110] direction initiating from the nucleation site, the appearance of curved dislocations, and buckling of the epi film around the nucleation site, all indicative of a strong bending force at the initiation site.