Improvement of CoSi2 thermal stability by cavity formation

We propose a method to improve the thermal stability of thin CoSi2 layers o n 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 larg e band of cavities created at the interface has extended the thermal stabil ity window by 125 degreesC with respect to the standard process. The improv ement has been related to the silicide grain-boundary pinning due to the in crease of the interface free energy contribution. (C) 2001 American Institu te of Physics.