EVOLUTION OF SI0.982C0.018 PSEUDOMORPHIC LAYER AFTER EXCIMER-LASER ANNEALING

We have studied the effect of excimer laser annealing on a high-qualit y Si0.982C0.018 pseudomorphic layer, using Fourier transform infrared (FTIR) spectroscopy, Raman spectrometry, and x-ray diffraction. The su bstitutional carbon concentration is found to decrease as a function o f fluence for 50 laser pulses performed at room temperature and vacuum , The strain profile evolution is obtained with x-ray diffraction and dynamical diffraction simulations. After melting, most of the strain i s released, and a new FTIR and Raman peak appears around 830 cm(-1). T his feature is attributed to the formation of SIC microprecipitates an d V-O asymmetrical centers. A mechanism for the substitutional carbon removal is proposed, It involves SiC precipitation and reaction betwee n V-O and substitutional carbon to form volatile CO. In the case of pu lsed laser induced epitaxy, we predict that the highest substitutional carbon content should be obtained with one laser pulse in an oxygen-f ree ambiant. From these results, it is inferred that pulsed-laser-indu ced epitaxy is suitable for the localized patterning of ultrashallow b uried Si1-yCy junctions. (C) 1998 American Institute of Physics.