Depth distribution and bonding states of phosphorus implanted in titanium investigated by AES, XPS and SIMS

The depth distribution of phosphorus implanted in titanium at 20 keV with doses ranging from 1 x 10(15) to 3 x 10(17) cm(-2) was investigated by AES, SIMS and XPS. For small doses (less than or equal to 10(16) cm(-2)) Gaussian-like phosphorus profiles have been observed. For doses >10(17) cm(-2) the depth profiles suggest that a TiP-like surface layer is formed without additional thermal treatment. In the implanted layer a certain amount of oxygen was found. Factor analysis of the spectra obtained during AES and XPS depth profiling proved that the surface region of the implanted samples is composed of Ti metal, surface oxide and Ti phosphide, which is produced at high doses. From P L-2,L-3 VV Auger spectra the existence of a second bonding state of phosphorus is deduced, which is distinguished from TiP by differences in the peak shape and position. This species is distributed mainly in a narrow profile located at a depth near the projected range of the phosphorus ions, i.e. in the region of maximum lattice defects. It is attributed to phosphorus on interstitial sites. The amount of this species reaches saturation for a dose of similar to 10(17) cm(-2). (C) 1998 John Whey & Sons, Ltd.