Ion irradiation stability of multilayered AlN/TiN nanocomposites

Abstract

Structural changes in multilayered AlN/TiN nanocomposites upon Ar(+) ion irradiation were investigated. Reactive sputtering was used to deposit (AlN/TiN) x 5 multilayers on Si(1 0 0), to a total thickness of similar to 270 nm. Argon was implanted at 200 keV, to 5 x 10(15)-4 x 10(16) ions cm(-2). The as-deposited multilayers had a very fine columnar nanocrystalline structure, the width of individual grains was up to similar to 10 nm. It was found that this immiscible system exhibits a high ion radiation stability, the AlN and TiN layers remaining well separated, with sharp interfaces. Ion irradiation induced small local density changes and only a slight increase in individual grains, in the region where most damage was deposited by the impact ions. For the highest irradiation fluence there was also some migration of Ti into AlN in this region, which was assigned to excess nitrogen within the AlN layers. Due to these small structural changes, ion irradiation enhanced the mechanical strength of the multilayered nanocomposites.