Mechanical Properties of Ion-Implanted Thin Films and Interfaces

Abstract

One of the areas of interest in the ion-beam modification of materials is that of alteration of specifically mechanical properties. To this end a method has been developed allowing in situ investigation of the stress, Young's modulus and mechanical hysteresis of small samples during and following ion-implantation. The samples are typically in the form of ~ 2 mm ⨉ 2 mm squares a few thousand angstroms thick, deposited on a ~ 50µ thick metal support, and forming a mechanical marginal oscillator. The measurement is carried out by flexing the samples at ~ 500 Hz under a servo-stabilized sinusoidal strain with a peak value in the range 0 to ~ 10−3. The accuracy of the method is typically ~ 1% or better for the measured quantities.Results are presented showing strain dependent (nonlinear) mechanical effects, thermal annealing effects, ion implantation of boron into copper and ion-beam mixing of copper films on aluminum substrates.