Formation mechanism of parallel twins related to Si-facetted dendrite growth

We propose a simple model to explain formation mechanism of parallel twins that are related to Si-facetted dendrite growth, and attempt to confirm its validity by in situ observations. The model involves the formation of a twin boundary at the {1 1 1} facet plane on the growth interface followed by formation of another twin parallel to the first one. Subsequently, a facetted dendrite grows parallel to the facet plane in this model. This growth behavior was successfully observed by growth experiments.