Effect of Excess Energy on Supersaturated Fe-IIIB Thin Films Formation by Ion Plating

Abstract

Fe-IIIB alloy thin lms are widely used in various types of actuators. In this study, Fe-Ga, Fe-Al, Fe-In alloy thin lms are deposited on a Si(100) substrate through an ion-plating process using a dual vapor-source. The composition of the thin lms was controlled by adjusting the deposition rate of Fe to the IIIB alloys. Deposition rates of Fe and IIIB alloys were measured by using a crystal oscillator. We investigate the effect of introduced excess energy during thin lm formation. In particular, the solid solubility limits for each type of Fe-based alloy thin lms are estimated and then compared using a Darken-Gurry plot, which was derived by applying the Hume-Rothery rules concerning electronegativity and the atomic radius of elements. The ion kinetic energy and the ionization rate of the evaporated particles were measured using a Langmuir probe and a Faraday cup, respectively. In addition, a multi-grid type electrostatic ion-energy analyzer was added in the plasma to obtain the ion temperature in order to acquire more precise excess energy value. Therefore, we attempt to study and control the excess energy required for Fe-IIIB alloy thin-lm formation and the solid solubility limit. These results are expected to contribute signi cantly to Fe-IIIB alloy thin-lm formation through the ion-plating process.