화학공학소재연구정보센터
Applied Surface Science, Vol.205, No.1-4, 240-248, 2003
Excimer laser crystallization of amorphous silicon carbide produced by ion implantation
4H-SiC was implanted with 100-250 keV Ge+ and Xe+ ions and doses of 1 X 10(14) to 1 X 10(16) cm(-1) at room temperature in order to produce 40-200 nm thick amorphous surface layers. The samples were irradiated with 1-50,000 pulses of a KrF excimer laser (248 nm wavelength, 30 ns pulse duration) using fluences of 150-900 mJ/cm(2) to investigate the crystallization process as a function of the laser parameters. Crystallization as well as redistribution of the impurity atoms were analyzed by Rutherford backscattering spectrometry and infrared reflection measurements. Phase transitions occurring during the irradiation were studied by means of time-resolved reflectivity measurements. In order to explain the observed phase transitions numerical analysis was performed by solving the inhomogeneous heat flow equation using the parameters of the corresponding phases. In this work, we give a consistent description of the experimental results by the numerical simulations for the given laser setup. Depending on the amorphous layer thickness, melting, solidification, and crystallization of the amorphous phase can be effectively controlled by both the laser fluence and the number of laser pulses. (C) 2002 Elsevier Science B.V. All rights reserved.