Recrystallization of Thin Gold Films: Influence on Their Electrical Properties

Abstract

Thin gold films evaporated in ultrahigh vacuum on amorphous substrates held at room temperature have very small crystals containing a great number of defects. Some of them (point defects, dislocations, twins) are, to a great extent, eliminated by a homogeneous heating which provokes a primary recrystallization between 80° and 150°C. This process lowers the initial residual electrical resistivity—more than 100% of the bulk value at 20 °C—to about 15%–30% after recrystallization. This residual resistivity is due mainly to the partly diffuse scattering of conduction electrons by the surfaces, for films thinner than 500 A. But for films thicker than 1600 A made by successive deposition of thinner layers, the density of grain boundaries is very high (β ≃ 0.6 × 105 cm/cm2). These defects are shown to contribute noticeably to the residual resistivity. The experimental value for their resistivity ΔρGB derived by this method is: 3 × 10−12β < ΔρGB < 4 × 10−12 Δ Ω cm.