CHEMICAL AND STRUCTURAL PROPERTIES OF THE Pd/Si INTERFACE DURING THE INITIAL STAGES OF SILICIDE FORMATION.
The initial stage of silicide formation of the Pd/Si interface has been studied during Pd deposition on the Si(111) surface using a combination of AES and TEM techniques. The formation of silicide was found to change the valence state of Si significantly as observed from the shape change of the Si LVV Auger spectra. The ratios of the normalized peak intensities were used to calibrate the composition and the thickness of the reacted layer. The calibration results coupled with TEM phase identification were indicative of uniform formation of the Pd//2Si compound even at room temperature up to about 10 A Pd coverage. Using thin Pd coverages of about 10 A, epitaxial growth of Pd//2Si was not observed on sputtered-cleaned Si surfaces. Crystalline order was clearly observed at the Pd//2Si/Si interface in annealed samples with less than 4 A Pd//2Si, indicating a relatively sharp interface with no significant amorphous-like structural disorder.