Synthesis of compound thin films by dual ion beam deposition. I. Experimental approach

The synthesis of compound thin films by dual ion beam deposition is described. In Part I of this two‐part paper, the experimental approach is presented, together with an analysis of composition for the aluminum‐nitrogen system. In the accompanying paper (Part II), the properties of Al‐N films are described. The dual beam technique supplies a deposition flux of Al from Ar+ ion beam sputtering of an Al target. Simultaneously, a low‐energy (100–500 eV) N+2 ion beam bombards the growing film. Using a measured ion beam gradient across the substrate holder, a wide range of arrival rate ratios (0≤N/Al≤1.6) is obtained in each deposition run, producing a composition range of (0.1≤N/Al≤1.0). The film composition varies linearly with N arrival flux and saturates at the composition of stoichiometric AlN. The incorporation probabilities of Al and N are close to unity for N/Al≊0, and decrease to 0.7 at N/Al=1.0. Preferential sputtering of Al occurs for N/Al 1. We discuss the accur...