Study of C, Al, Si and Ge sputtering yield amplification by ion beam analysis and co-sputtering simulation software

Abstract

In 1991 Berg discovered the phenomenon he called sputtering yield amplification (SYA). He considered that the explanation of the phenomenon was related to the difference in the masses of the atoms involved, i.e. the target atoms, the incident ion, usually Ar, and the added atoms, which were heavier than the target atoms. Today, with additional experimental results, it is thought that the surface binding energy is also involved. In this study, thin films of C, Si, and Ge were deposited using targets with small pieces of W added to the different targets, and Al films were deposited with small pieces of Ti added to the target. The spatial distribution of both the total deposit and that of each element was measured, and the same distributions were simulated using the co-sputtering simulation (Co-SS) software. The simulation parameters of the Co-SS software are the angular distribution of the atoms sputtered from the target and the sputtering yields. The analysis showed that the addition of one, two and three pieces of W to the C and Si targets resulted in a SYA of 66%, 35% and 43%, and 15%, 42% and 74%, respectively. However, there was no change in the sputtering yield of Ge with the addition of W. The SYA for the Al target with the pieces of Ti was 9%, 23% and 15%. The angular distribution of the atoms sputtered from the targets was also affected by the presence of W or Ti inserts as well as the W atomic concentration. The elementary spatial distribution, the thin film thickness and the W atomic percentage were measured by Rutherford backscattering spectrometry, profilometry and x-ray photoelectron spectroscopy techniques, respectively.