Observation of defects in laser-crystallized polysilicon thin films by hydrogenation and Raman spectroscopy

The relationship between defects and Si-hydrogen bonds in laser-crystallized poly-Si thin films was investigated by Raman spectroscopy. Hydrogenation was performed using two techniques, plasma excitation and a low-damage technique using a hot-wire as the catalyzer. At least six peaks were detected in the Raman spectra after plasma hydrogenation: two were sharp and Lorentzian shaped even though they appeared in the region of local-vibration modes. These peaks were attributed to defects induced by plasma damage and laser crystallization. It was deduced that defects undetectable by Raman spectroscopy could be detected as Si-hydrogen bonds by hydrogenation.