Improvement of CoSi2 thermal stability by cavity formation

We propose a method to improve the thermal stability of thin CoSi2 layers on polycrystalline silicon substrates. Nitrogen atoms have been implanted at 55 keV to a dose of 5x10(15)/cm(2) through a 70 nm silicide layer in order to locate the implanted peak near the silicide/silicon interface. The large band of cavities created at the interface has extended the thermal stability window by 125 degreesC with respect to the standard process. The improvement has been related to the silicide grain-boundary pinning due to the increase of the interface free energy contribution.