Laser induced metastable phases in microcrystalline silicon

It has been found using Raman spectroscopy that metastable Si phases reversibly appear in silicon microparticles (µ-Si) due to local heating on increasing the power of a He–Ne excitation laser from 0.03 to 3 mW. Prolonged annealing of these phases by laser radiation makes it possible to estimate that local heating occurs to a temperature of ∼250 °C rather than 1000 °C as it was believed previously.