- Tan, T.Y. and Ho, P.S. and Tsu, R., Temperature distribution and microstructure in small-diameter laser beam annealed amorphous silicon,
AIP Conf. Proc. (USA) no. 50
pp. 463 - 9 .
(last updated on 2007/04/10)
Temperature distribution associated with the annealing of amorphous Si by a finite Gaussian laser beam is carried out by considering the three-dimensional heat flow problem. A power density requirement for inducing melting is established. Temperature distribution profiles showed that the isotherms can spread well outside the nominal beam dimension, partial melting of the amorphous Si surface region is possible, and that thermal gradient can be very large over a short distance. At the edge of laser annealed spots, the authors observed regions containing dislocations and polysilicon. By examining the isotherms, the presence of these defects may be explained in terms of growth of single crystal Si competing with random grain nucleation, and the large thermal gradient and cooling rate may be responsible for the typical `thermal non-equilibrium' appearance of such dislocations
amorphous semiconductors;annealing;dislocations;elemental semiconductors;heat transfer;laser beam effects;melting;silicon;transmission electron microscope examination of materials;