151. Influence of ultra-low ethylene partial pressure on microstructural and compositional evolution of sputter-deposited Zr-C thin films
- Author
-
Hicham Zaid, Joshua Fankhauser, Pascal Berger, Suneel Kodambaka, Tyson C. Back, Angel Aleman, Chao Li, Koichi Tanaka, Mark S. Goorsky, Department of Materials Science and Engineering, University of California [Los Angeles] (UCLA), University of California-University of California, Department of Aerospace and Mechanical Engineering [Los Angeles] (AME), University of Southern California (USC), Laboratoire d'Etudes des Eléments Légers (LEEL - UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Air Force Research Laboratory (AFRL), United States Air Force (USAF), Air Force Office of Scientific Research (AFOSR, Dr. Ali Sayir) under Grant # FA9550-14-1-0106 and # FA9550-18-1-0050, Office of Naval Research (Dr. Chagaan Baatar) under Grant #N00014-12-1-0518, Japanese Student Service Organization (L16111111026), UCLA department of materials science and engineering, National Science Foundation (NSF CMMI) grant #1563427 (Dr. Kara Peters), the Electron Imaging Center for NanoMachines supported by NIH (1S10RR23057) and the California NanoSystems Institute at UCLA, University of California (UC)-University of California (UC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
010302 applied physics ,Materials science ,Analytical chemistry ,[CHIM.MATE]Chemical Sciences/Material chemistry ,02 engineering and technology ,Surfaces and Interfaces ,General Chemistry ,Partial pressure ,Sputter deposition ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,01 natural sciences ,Surfaces, Coatings and Films ,Amorphous solid ,X-ray photoelectron spectroscopy ,Sputtering ,0103 physical sciences ,Materials Chemistry ,Crystallite ,Thin film ,0210 nano-technology - Abstract
International audience; Zr-C thin films are grown on single-crystalline MgO(001) substrates via ultra-high vacuum dc magnetron sputtering of Zr target in 10 mTorr Ar-C$_2$H$_4$ gas mixtures with ethylene partial pressures ($P_{C2H4}$) between 2 × 10$^{−7}$ Torr and 2 × 10$^{−4}$ Torr at substrate temperature $T_s$ = 923 K and using $P_{C2H4}$ = 2 × 10$^{−6}$ Torr at 723 K ≤ $T_s$ ≤ 1123 K. The as-deposited layer microstructure and composition are determined using X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. We find that the layers sputter-deposited at $T_s$ = 923 K using the lowest $P_{C2H4}$ = 2 × 10$^{−7}$ Torr are polycrystalline, close-packed hexagonal structured Zr:C solid solutions. At higher $P_{C2H4}$ = 2 × 10$^{−6}$ Torr and 2 × 10$^{−5}$ Torr, we obtain films composed of free‑carbon (C) and NaCl-structured ZrC$_x$, $x$ ≤ 1. The amount of C increases 104% with ten-fold increase in $P_{C2H4}$ from 2 × 10$^{−6}$ Torr to 2 × 10$^{−5}$ Torr. At the highest $P_{C2H4}$ = 2 × 10$^{−4}$ Torr, the layers are X-ray amorphous with $\sim$49 at.% C. Films grown at 723 K ≤ $T_s$ ≤ 1123 K using constant $P_{C2H4}$ = 2 × 10$^{−6}$ Torr exhibit qualitatively similar microstructures, irrespective of $T_s$, composed of dense columnar ZrC$_x$ grains surrounded by C and corrugated surfaces. Our results suggest that the compositional and microstructural evolution of Zr-C films during reactive sputter-deposition of Zr is highly sensitive to ethylene partial pressure, with as little as 0.02% of the total pressure sufficient at $T_s$ ≥ 723 K to obtain ZrC$_x$ films.
- Published
- 2020