ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
Thin (90 nm) a-Si:H films on Corning 7059 glass substrates have been crystallized by120 fs pulses of Ti:sapphire and nanosecond pulse XeCl and KrF excimer lasers. Initial films weredeposited using low-temperature plasma enhanced deposition technique. The structural properties ofthe films were characterized using the spectroscopy of Raman scattering, excited by the argon laser(line 514.5 nm) and using electron microscopy. For the femtosecond pulse treatments the ablationthreshold was found to be some more than 65 mJ/cm2. When pulse energy density was lower than~30 mJ/cm2 no structural changes were observed. In optimal regimes the films were found to befully crystallized with needle grain structure, according to the Raman scattering and electronmicroscopy data. Estimates show the pulse energy density was lower than the Si melting threshold,so non-thermal “explosive” impacts may play some role. The main result in nanosecond XeCl andKrF laser pulse crystallization is the narrower window between beginning of crystallization andablation for KrF laser (wavelength 248 nm) than for the XeCl laser (wavelength 308 nm). So, thepossibility of the femtosecond and nanosecond laser pulses to crystallize a-Si films on nonrefractory glass substrates was shown. The results obtained are of great importance formanufacturing of polycrystalline silicon layers on non-refractory large-scale substrates for giantmicroelectronics
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.131-133.479.pdf
