Effect of overlayers on the instability of copper island films

The results of investigations carried out on the effect of overlayers of Al2O3, SiO2 and MoO3 on the instability of discontinuous copper films at room temperature and at 125 K, are reported. For one film, long-term stability was studied for more than 1500 h. The overlayers are inadequate in preventing movement of the islands both at room temperature and at 125 K and in providing protection against attack by atmospheric gases. The films, when exposed to the atmosphere, show a large increase in resistance in a well-defined pressure range of ≃5 × 10-2 torr, corroborating our earlier findings. The I-V characteristics at 125 K were nonlinear, the non-linearity being attributed to field-induced structural changes. © 1988 Chapman and Hall Ltd.