A study of trench-edge defect formation in (001) and (011) silicon recrystallized by solid phase epitaxy

Abstract

Trench-edge defects formed during epitaxial recrystallization of trench-bounded amorphized silicon (a-Si) regions are examined as a function of Si substrate crystal orientation. In Si (001), rectilinear a-Si features having edges aligned with the crystal’s in-plane ⟨110⟩ directions recrystallize leaving trench-edge defects along all trench edges, whereas the identical features in Si (011) recrystallize without trench-edge defects along trench edges parallel to the crystal’s in-plane ⟨100⟩ direction and with trench-edge defects along trench edges parallel to the crystal’s in-plane ⟨110⟩ direction. The positions and lateral extent of these trench-edge defects suggest that their source is defective epitaxy on slow-growing {111} planes formed during recrystallization. A heuristic model proposed to explain the formation of these {111} planes correctly predicts the essentially defect-free recrystallization seen for rectilinear a-Si features in Si (001) having edges aligned with the crystal’s in-plane ⟨100⟩ directions, but cannot completely account for the distinctively curved growth fronts sometimes seen at intermediate stages of recrystallization.