Crystallization of amorphous Si0.5Ge0.5 films studied by means of in-situ X-ray diffraction and in-situ transmission electron microscopy

The effect of B and P doping on the crystallization kinetics of amorphous S i0.5Ge0.5 films was studied by means of in-situ X-ray diffraction (XRD) and insitu transmission electron microscopy (TEM). Amorphous Si0.5Ge0.5 films, doped and undoped, were deposited by the molecu lar beam method on SiO2/Si(001) substrates and annealed at temperatures bet ween 500 and 600 degrees C. The crystalline fraction an the films was evalu ated by following the intensity of the (220) reflection, obtained by in-sit u XRD, as a function of time. It is demonstrated that the crystallization k inetics follow the Avrami formalism. The overall activation energy of cryst allization was found to be 3.49 eV for P-doped (10(20) cm(-3)) Si0.5Ge0.5 f ilms. In addition, crystallization parameters such as the incubation time, the nu cleation rate and the grain growth rate were determined directly by in-situ TEM. The activation energies for grain growth and for the overall transfor mation were found to be 2.7 and 2.4 eV respectively for undoped Si0.5Ge0.5 films. The films which were highly doped with B and P showed higher crystal lization rate than the undoped films did.