Polysilicon recrystallization by CO₂ laser heating of SiO ₂

CO2 laser emission matches the absorption of optical phonons in SiO2. This fact was used to couple the laser energy into a layer of SiO2 (510 nm) deposited over polysilicon (225 nm), which was deposited on thermally grown SiO2 (860 nm). In this manner, recrystallization of the polysilicon was achieved with a mosaic pattern of grains having sizes in the 1-30-μm range.