Complementary Studies of Aluminum Thin Films: Resistivity and Real Structure

The results of complex studies of the temperature dependence of the electrical resistance of thin magnetron Al films on their structural characteristics—morphology, surface roughness, microstructure, and density—are presented. In order to establish a fundamental connection between the specific resistance and the structural features of the films, they are deposited on standard Si(111) substrates in a two-stage growth mode with the formation of homobuffer layers (HBL) in the temperature range from 293 to 800 K. Structural characterization of the samples is performed using scanning force and electron microscopy, X-ray diffractometry, and reflectometry. It is shown that the magnitude and temperature dependence of the specific resistance of aluminum films can be changed by varying the growth conditions of the HBL, which allows deposition of films with different density profiles across the thickness. It is found that a magnetron 120-nm aluminum film on a 700 K HBL with a constant density of 2.66 g/cm3 has a specific resistance of $${{\rho }_{{RT}}}$$ = 2.69 μOhm cm and Tc = 1.22 K. Al films with variable density have a residual resistance of ∼30 μOhm cm. The main contribution to the resistance of such films is made by intergranular regions with lower density, which is reliably recorded by the X-ray reflectometry method.