Large Area Subgrain-Boundary-Free Sot Induced by Thermal Gradient Control of Transitional Seeded-Growth

Abstract

ABSTRACTThe transitional region of subgrain-boundary-free crystal to subgrain-boundary-laced crystal formed during the initial stage of energy-beam induced seeded recrystallization of thin film silicon on an insulator has been examined to study the primary cause of subgrain boundary formation and the conceptual basis of its suppression. Observations include the systematic variation of: facet, cellular, and dendritic features; subgrain boundary directions and spacings; and the stable growth distance as a function of silicon film thickness and energy beam density. A temperature gradient argument based on constitutional supercooling theory has been used to explain these observations. There are indications that an increased thermal gradient at the solidification front can suppress the onset of growth instability for large area, defect free growth of SOI.