Morphological Characteristics of Au Films Deposited on Ti: A Combined SEM-AFM Study

Francesco Ruffino,Maria Grimaldi

doi:10.3390/coatings8040121

Francesco Ruffino, Maria Grimaldi

Open Access

https://doi.org/10.3390/coatings8040121

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Abstract

Deposited Au films and coatings are, nowadays, routinely used as active or passive elements in several innovative electronic, optoelectronic, sensing, and energy devices. In these devices, the physical properties of the Au films are strongly determined by the films nanoscale structure. In addition, in these devices, often, a layer of Ti is employed to promote adhesion and, so, influencing the nanoscale structure of the deposited Au film. In this work, we present experimental analysis on the nanoscale cross-section and surface morphology of Au films deposited on Ti. In particular, we sputter-deposited thick (>100 nm thickness) Au films on Ti foils and we used Scanning Electron Microscopy to analyze the films cross-sectional and surface morphology as a function of the Au film thickness and deposition angle. In addition, we analyzed the Au films surface morphology by Atomic Force Microscopy which allowed quantifying the films surface roughness versus the film thickness and deposition angle. The results establish a relation between the Au films cross-sectional and surface morphologies and surface roughness to the film thickness and deposition angle. These results allow setting a general working framework to obtain Au films on Ti with specific morphological and topographic properties for desired applications in which the Ti adhesion layer is needed for Au.

Highlights

Deposited Au films and coatings are, nowadays, routinely used as active or passive elements in several innovative electronic, optoelectronic, sensing, and energy devices [1,2,3]
On the basis of the previous considerations, the aim of the present paper is to report on the experimental analysis of the nanoscale cross-section and surface morphology of thick Au films
We report cross-sectional and plan-view Scanning Electron Microscopy (SEM) micrographs of the Au films deposited on Ti in the various conditions

Summary

Introduction

Deposited Au films and coatings are, nowadays, routinely used as active or passive elements in several innovative electronic, optoelectronic, sensing, and energy devices [1,2,3] These technologies require exploitation of the electronic, magnetic, optical, mechanical and thermal properties unique to metallic materials. With the approaching of the quantum electronic devices with a projection of a gate length of 4–5 nm [3] it is likely that metal contacts will play a crucial role It can be anticipated, that the successful downscaling demand high-performance contacting metals in terms film thickness, crystallographic phase, and surface/interface morphology; (b) the mechanical properties of metallic

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