CHARACTERIZATION OF AMORPHOUS PTSI SCHOTTKY CONTACTS ON SI

Very thin (30-60Å) amorphous PtSi Schottky contacts on (100) Si have been studied by current-voltage and activation energy techniques in the temperature range of 325-55K. The silicide layers have been prepared by magnetron sputtering of platinum onto heated silicon substrates, followed by in situ annealing in vacuum. Angle-resolved XPS, electron diffraction and high resolution TEM were used to study the composition and microstructure of the films. The results show amorphous PtSi structure, with isolated grains growing epitaxially to the silicon substrate. The silicide-Si interface appears to be quite smooth. No interfacial contamination layer was detected. In films exposed to the air traces also of Pt2Si and excess oxygen in the surface layer was found. The diodes, fabricated with the thin amorphous PtSi contacts have nearly ideal and reproducible characteristics, with barrier height of 0.895 ± 0.005 eV at room temperature, and about 0.02 eV higher at T = OK, as extrapolated from I-V measurements. The plot in In (lo/T2) vs 1/T yields the same barrier height value. The ideality factor does not change significantly over quite large temperature ranges. © 1990.