Short-pulse laser-induced crystallization of intrinsic and hydrogenated amorphous germanium thin films
作者:
M. Mulato,
D. Toet,
G. Aichmayr,
P. V. Santos,
I. Chambouleyron,
期刊:
Journal of Applied Physics
(AIP Available online 1997)
卷期:
Volume 82,
issue 10
页码: 5159-5166
ISSN:0021-8979
年代: 1997
DOI:10.1063/1.366320
出版商: AIP
数据来源: AIP
摘要:
We report on the laser crystallization of intrinsic (a-Ge) and hydrogenated (a-Ge:H) amorphous germanium thin films using short, i.e., ns range, laser pulses. The influence of hydrogen on the phase transitions was investigated by monitoring the reflectance of the sample during laser irradiation. We determined the thresholds for melting (36 mJ/cm2)and for surface damage (66 mJ/cm2)of the a-Ge film. In a-Ge:H, hydrogen effuses on a short time scale (10 ns) upon laser irradiation. The effusion leads to the formation of a lifted-off (100 nm thick) crystalline Ge membrane, leaving behind a rough and incompletely crystallized surface. In a-Ge, on the other hand, no surface disruption is observed. The Raman spectra of hydrogenated samples are dominated by stress effects, while those corresponding to non-hydrogenated samples are dominated by crystallite size distribution effects. We also conclude that laser-induced annealing, carried out by applying several pulses with increasing intensity, can be used as a tool for the crystallization of a-Ge:H samples without hydrogen-induced surface damage. ©1997 American Institute of Physics.
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