A Study of Al/PtSi/Si Thin Film Reaction Kinetics by X-Ray Diffraction

PtSi has been widely used in the electronics industry as a material for both ohmic contacts and Schottky diodes. It is known that the use of aluminum based metallurgies in contact with PtSi can lead to electrical instabilities when processing requires temperatures in excess of ~300°C. The aluminum reacts with the PtSi film forming PtA12 as the reaction product according to the reaction PtSi + 2A1 + PtAl2 + Si. The kinetics and mechanism of PtAl2 formation in the thin film system Al/PtSi/Si were studied in the temperature range 320-420°C, using X-ray diffraction. The data obtained is represented in terms of the generalized kinetics equation X = 1 - exp [¿K(T)tn] and yields an activation energy of 2.2 ± 0.2 eV/mole.