Hot Electron Transport In Thin Copper Films PDF Download

In principle. the resistivity of bulk face centered cubic (fcc) materials should not depend on the orientation due to the fact that the conductivity tensor is single valued. However, we show that this conclusion is not valid for thin films. Deposition of highly oriented aluminum, silver, and copper films on amorphous substrates using the partially ionized beam (PIB) technique exhibits a resistivity that is strongly correlated with the texture, i.e., the tighter the texture, the lower the film resistivity. We model the film as an array of grains whose grain boundaries can be considered as delta function potentials for electron scattering, and the strength of the potentials can be calculated from the measured resistivity of the films. On the other hand, the fiber texture distribution of the films is obtained from X-ray pole figure measurements, and Monte Carlo simulations are then performed using these data to determine the average dislocation density at the grain boundaries due to the grain-to-grain crystallographic mismatch. We show that the transmittance coefficient for electron scattering, and therefore, the film resistivity, is a monotonically increasing function of the average dislocation density. We, therefore, conclude that the structure of grain boundaries in a thin film provides the necessary mechanism by which the resistivity of an fcc cubic metal can depend on the texture.