Asymmetric intermixing in Pt/Ti

TL;DR

This study investigates asymmetric atomic intermixing in Pt/Ti multilayers using simulations and experimental profiling, revealing significant differences in interdiffusion depending on layer order and highlighting the complexity of underlying mechanisms.

Contribution

It provides the first combined experimental and simulation analysis of intermixing asymmetry in Pt/Ti multilayers, demonstrating the phenomenon and its dependence on layer configuration.

Findings

Intermixing is asymmetric in Pt/Ti and Ti/Pt multilayers.

Simulation results align with experimental measurements of interface broadening.

Interdiffusion of Pt into Ti is unexpectedly enhanced in certain configurations.

Abstract

The ion-sputtering induced intermixing is studied by Monte-Carlo TRIM, molecular dynamics (MD) simulations, and Auger electron spectroscopy depth profiling (AES-DP) analysis in Pt/Ti/Si substrate (Pt/Ti) and Ta/Ti/Pt/Si substrate (Ti/Pt) multilayers. Experimental evidence is found for the asymmetry of intermixing in Pt/Ti, and in Ti/Pt. In Ti/Pt we get a much weaker interdiffusion than in Pt/Ti. The unexpected enhancement of the interdiffusion of the Pt atoms into the Ti substrate has also been demonstrated by simulations. We are able to capture the essential features of intermixing using TRIM and MD simulations for ion-beam sputtering and get reasonable values for interface broadening which can be compared with the experimental measurements. However, the origin of the asymmetry remains poorly understood yet.