Nano-indentation of ion-beam modified HfN/Si system: Identification of theamorphized inter-layer

The work aims to clarify the considerable softening registered for the HfN/ Si system after its bombardment with energetic ions (E=1, 2.5 and 5 MeV, fl uence=10(14) Au++ cm(-2)). The mechanical properties of the virgin and ion- modified films were characterized using the depth-sensing indentation exper iments performed under maximum indentation load ranging from 2 to 50 mN. Th e surface deformation in the vicinity of the contact with a triangular inde nter was modeled by the finite element simulation of the axisymmetric-inden ter penetration into the hard-film/soft-substrate system. The applied appro ach allowed us to attribute the observed difference in hardness of virgin a nd ion-treated samples to the structural changes which have been induced in the silicon substrate by bombarding ions. The calculated results led us to the conclusion that bombardment with energetic Au-ions resulted in formati on of the interlayer of amorphous silicon, right under HFN film. The presen t work aims to prove that the depth-sensing experiments supplemented by the finite-element calculations provide a new, powerful method of characterizi ng the multilayer structures. (C) 1999 Elsevier Science B.V. All rights res erved.