2024 Bill Sproul Award and Honorary ICMCTF Lecture Recipient

Purpose

The Bill Sproul Award and Honorary ICMCTF lectureship is to recognize the achievements of a mid-career researcher who has made outstanding scientific and/or technological contributions in areas of interest to the Advanced Surface Engineering Division (ASED) of the AVS, with an emphasis in the fields of surface engineering, thin films, and related topics.

Biography

Gregory Abadias is a Professor at the Physics Department of the University of Poitiers, and Deputy Director of the Department of Physics and Mechanics of Materials, at Pprime Institute, France. He received his Ph.D. degree in materials science in 1998 at the National Polytechnic Institute of Grenoble (INPG), and he is currently the group leader of thin films activities at Pprime Institute. He conducts research on a range of topics related to nanoscale thin films, including mechanical, electrical, and optical properties of metallic, nitride, or oxide systems, as well as hard and protective coatings in the form of nanocomposites or multilayers. His current research interests focus on the understanding of thin film growth dynamics using real-time and in situ diagnostics as well as computational modeling, with a main emphasis on growth manipulation strategies to tailor morphology and stress evolution in sputter-deposited metal layers.

He has co-authored more than 160 papers in peer-reviewed journals and one book chapter on stress in PVD thin films. He was member-elected to the Scientific Council of the Physics Institute of CNRS (2019-23), and he is currently standing at the Condensed Matter Division of the French National Committee of Scientific Research (CoNRS -section 05). He was elected as an Executive Committee member of the Advanced Surface Engineering Division (ASED) of AVS (2021-22) and has been the French representative of the Surface Engineering Division of IUVSTA since 2022. He has been involved in the organization of several symposia or workshops at international conferences (ICMCTF, EMRS) and has served as Editor of the Surface and Coatings Technology journal since 2016.

Abstract

“When Stressed Condensed Matter Reveals Its Ultimate Secrets: Thin Film Growth Dynamics Probed by Real-Time Diagnostics”

Monday, May 20, 2024 – 11:00 AM (PT)
Room: Palm 3-4

Metallic thin layers grown by physical vapor deposition (PVD) are ubiquitous in many technological areas, as key components of optoelectronic devices, architectural glazing or sensors. Due to the non-equilibrium nature of PVD, the formation of a thin solid layer from the condensation of a vapor flux onto a substrate is inevitably accompanied by the development of a stress build-up [1]. The accumulated stress can significantly reduce the performance, integrity, and durability of the material, so that a fundamental understanding of intrinsic stress sources, being either of tensile or compressive type, is needed. In recent years, significant progress has been gained thanks to the potentiality offered by real-time and in situ diagnostics [1-4].

We will present some recent advances on stress evolution during the growth of polycrystalline metal layers based on a series of real-time wafer curvature and X-ray synchrotron experiments, and physical models. In contrast to epitaxial systems, where the stress evolution is often dominated by interface-related stresses, polycrystalline layers growing on weakly interacting substrates reveal a complex stress evolution resulting from a subtle interplay between interface formation and microstructural evolution. Through several illustrative examples covering a broad range of sputter-deposition conditions (working pressure, temperature, particle flux, bias voltage, ionization degree) and spanning different film/substrate interactions, the influence of kinetics and energetics on growth morphology and stress development will be discussed [5], with main emphasis laid on the early growth stages. The impact of energetic particle bombardment on the compressive stress build-up observed during sputter-deposition of refractory metal layers will be explored, and the results discussed in the frame of a kinetic model which includes the influence of grain size, deposition rate, and adatom mobility [6].

We will also show that nanoscale phase transformation during the course of film growth can be unraveled from the combination of real-time optical/electrical and surface-sensitive X-ray methods [3,4,7]. Finally, recent findings on the impact of gas additives and wetting agents on the growth morphology of ultrathin Ag layers will be highlighted, with the ultimate goal to produce ultrathin and ultrasmooth Ag layers for use as transparent conductive electrodes [8]. On a broader context, the knowledge gained from these real-time and in situ diagnostics may provide guidelines for efficient growth manipulation strategies in order to target specific applications.

References

[1] G. Abadias et al., “Review Article: Stress in thin films and coatings: Current status, challenges, and Prospects”, J. Vac. Sci. Technol. A 36 (2018) 020801

[2] E. Chason, P. Guduru, “Tutorial: Understanding residual stress in polycrystalline thin films through real-time measurements and physical models”, J. Appl. Phys. 119 (2016) 191101

[3] A. Fillon, G. Abadias et al., “Influence of Phase Transformation on Stress Evolution during Growth of Metal Thin Films on Silicon”, Phys. Rev. Lett. 104 (2010) 096101

[4] J. Colin et al., “In Situ and Real-Time Nanoscale Monitoring of Ultra-Thin Metal Film Growth Using Optical and Electrical Diagnostic Tools”, Nanomaterials 10 (2020) 2225

[5] A. Jamnig, N. Pliatsikas, K. Sarakinos, G. Abadias, “The effect of kinetics on intrinsic stress generation and evolution in sputter-deposited films at conditions of high atomic mobility”, J. Appl. Phys. 127 (2020) 045302

[6] E. Chason et al., “A kinetic model for stress generation in thin films grown from energetic vapor fluxes”, J. Appl. Phys. 119 (2016) 145307

[7] B. Krause, G. Abadias et al., “In Situ Study of the Interface-Mediated Solid-State Reactions during Growth and Postgrowth Annealing of Pd/a-Ge Bilayers”, ACS Appl. Mater. Interfaces 15 (2023) 11268

[8] K. Sarakinos et al., “Unravelling the effect of nitrogen on the morphological evolution of thin silver films on weakly-interacting substrates”, Appl. Surf. Sci. 649 (2024) 159209

Acknowledgements: This work is part of the IRMA project funded by the ANR and DFG.