Electrical Contact and Adhesion Modification Produced by High Energy Heavy Ion Bombardment of Au Films on GaAs

Thin gold films over GaAs wafers with different dopants (Cr, Si, Te, and Zn) were used to study the role of he substrate electronic properties in the electrical contact and adhesion modification induced by MeV/nucleon heavy ion bombardment. The enhanced adhesion was studied using a scratch test; the results show very different modifications of adhesion depending on the bulk electronic properties of the substrate. The sample with a Cr compensation doped substrate showed enhancement in adhesion for beam doses as low as 1012 ions/cm2, but Si and Te doped (n–type) substrates showed a sudden enhancement in adhesion for doses around 1014 ions/cm2. Samples with Si and Te doped substrates were used to sudy the bombarding ion dE/dx dependence of the induced adhesion for 19F and 35C1 ions with electronic stopping power ranging from 161 eV/A to 506 eV/A. In this range the dose threshold fgfjhe ops! of induced adhesion has a power law dependence, D = D0(dE/dx)− (1.90 ± 1.0)