Microstructure and resistivity of Au-B supersaturated solid-solution films prepared by sputter deposition

Abstract

• A series of Au–B films was deposited by magnetron sputtering. • Au-B supersaturated solid solutions without AuB 2 compounds confirmed in the films. • The microstructure of the Au–B supersaturated solid-solution films was studied. • The relationship between the resistivity and b content in the films was revealed. • The Au–B supersaturated solid-solution films were stable at room temperature. Au-B films are of interest for superconductor and hohlraums materials. A series of gold-boron (Au-B) films with different B contents has been deposited by magnetron sputtering of Au-B pseudo-alloy targets in an Ar atmosphere. The B atomic concentration of the Au-B films was varied by adjusting the B contents of the Au-B targets and sputtering pressure. The composition, microstructure and resistivity of the Au-B films were investigated by X-ray photoelectron spectrometry, X-ray diffraction and the four-probe method. Due to the mutually immiscibility of Au and B, non-equilibrium supersaturated solid solutions of B in Au with nanocrystalline microstructures instead of AuB 2 metal diboride were observed in the as-deposited films. With increasing B content, the average grain size of the films decreased and the d -spacing of Au (111) increased. The resistivity of the Au-B supersaturated solid-solution films was linearly related to the B content and no superconductivity was observed. The structure of the Au-B films was stable at room temperature for a long time, while annealing caused phase transition.