ROUGHNESS IMPROVEMENT AND HARDNESS ENHANCEMENT IN NANOSCALE AL ALN MULTILAYERED THIN-FILMS/

Al/AlN multilayered thin films with periodic thickness lambda less tha n 24 nm were developed by ion beam assisted deposition. A considerably small surface roughness comparable to that of the silicon substrate a nd much smaller than those of both monolithic Al and AlN films was obt ained. Over the investigated range of lambda, all the multilayers are harder than the homogeneous AlN film, and a significant hardness enhan cement by a factor of similar to 2 over that of the AlN film was obser ved in the multilayer with lambda of 6 nm. Moreover, the hardness enha ncement is not at the expense of the multilayer toughness, with the mu ltilayer Al/AlN films showing improved plasticity as compared with the AIN film. (C) 1997 American Institute of Physics.