CO2 Laser Crystallization of Silicon on Bulk Fused Silica

ABSTRACTA CO2 laser beam was used to heat bulk fused silica which had previously defined Si3N4 and Si02 encapsulated LPCVD polysilicon islands (25,μm × 100μm) on its surface. The recrystallization process produces single crystal islands under a wide variety of laser treatment parameters. Under certain conditions, the recrystallized islands exhibit a (100) plane parallel to the substrate. These results are the first demonstration of oriented single crystal thin film growth using island predefinition, which eliminates thermal stress induced microcracking resulting from the mismatch in expansion between silicon and bulk fused silica.