Laser scan registration for lateral epitaxy of silicon-on-insulator stripes on silicon substrates

Abstract

An improved technique for seeded laser recrystallization of silicon-on-insulator stripes has been developed using a slanted elliptical beam and a computer-controlled system to register laser scans to alignment marks on the silicon wafer. After the wafer position is automatically determined by searching for alignment marks with a low-power beam, a raster is generated parallel to the device features, and the aligned laser beam is swept across the wafer. The dependence of the defect structure of the recrystallized films on the parameters used for scanning and the resulting thermal gradients are described. With the proper choice of parameters, defect-free, single-crystal silicon films over oxide stripes up to 65 μm wide have been obtained.