NONDESTRUCTIVE CHARACTERIZATION OF THE UNIFORMITY OF THIN COBALT DISILICIDE FILMS BY RAMAN MICROPROBE MEASUREMENTS

The ability of microRaman spectroscopy for the non-destructive charact erization of the uniformity of thin silicide films on Si is analyzed. The technique is applied to characterize thin polycrystalline and epit axial CoSi2 films. The absorption coefficient of these films, alpha, a t the excitation wavelength of 514.5 nm is determined from Raman scatt ering measurements in combination with Rutherford backscattering spect rometry. Using this value, the thickness uniformity of the layers can be investigated by microRaman spectroscopy with a lateral resolution b elow the size of the devices to be defined on the structures. Moreover , even if alpha is not known, the product ad can be calculated in a st raightforward way from Raman measurements, where d is the film thickne ss. By monitoring this product, the homogeneity of the layers can be a nalyzed. The results obtained are discussed in terms of the different processing of the layers. Finally, the ability of the technique for th e characterization of the films is studied as a function of their thic kness.