Photoemission study of fully silicided Pd2Si gates with interface modification induced by dopants

Work function shifts for fully silicided (FUSI) Pd2Si gates with BF2 and P predoping, originally observed as the flatband voltage shifts in metal-oxide-semiconductor (MOS) diodes, were also reproducible for backside x-ray photoelectron spectroscopy measurements. The Pd composition ratios of FUSI layers were reduced in the vicinity of the gate SiO2 layer, which directly affects apparent work function in the MOS system. However, other non-negligible changes, such as pileup of predoped elements and Pd precipitation, were also found for the predoped cases. The work function shift by predoping should be considered to be a result of interaction of such multiple factors.