Selective area crystallization of amorphous silicon using micro-patterned SiO₂ capping layer

We have investigated a new crystallization technique using selective area heating (SAH) with a micro-patterned SiO₂ capping layer. The purpose of SAH is to improve performance of amorphous silicon films in the presence of glass substrates with extremely low thermal budgets. The glass substrate had no damage even though the temperature of the thin heater was above 900 °C because radiant thermal energy was limited to a well-defined selective area. To reduce the crystallization time and crystallize only the active area, a micro-patterned SiO₂ capping layer was used. The annealing time of SAH was under 16 W for 2 min. The crystallinity of poly-Si was investigated by Raman spectroscopy. A 400 nm-thick SiO₂ film developed higher crystallinity than other SiO₂ thickness films after SAH for 80 s. The crystallinity was 94%. The results show that a SiO₂ capping layer can store thermal energy. We suggest SAH as a new crystallization technique for large area electronic device applications.