%0 Journal Article %T Influence of ultra-low ethylene partial pressure on microstructural and compositional evolution of sputter-deposited Zr-C thin films %+ Department of Materials Science and Engineering %+ Department of Aerospace and Mechanical Engineering [Los Angeles] (AME) %+ Laboratoire d'Etudes des Eléments Légers (LEEL - UMR 3685) %+ Air Force Research Laboratory (AFRL) %A Zaid, Hicham %A Aleman, Angel %A Tanaka, Koichi %A Li, Chao %A Berger, Pascal %A Back, Tyson %A Fankhauser, Joshua %A Goorsky, Mark, S. %A Kodambaka, Suneel %Z Air Force Office of Scientific Research (AFOSR, Dr. Ali Sayir) under Grant # FA9550-14-1-0106 and # FA9550-18-1-0050 %Z Office of Naval Research (Dr. Chagaan Baatar) under Grant #N00014-12-1-0518 %Z Japanese Student Service Organization (L16111111026) %Z UCLA department of materials science and engineering %Z National Science Foundation (NSF CMMI) grant #1563427 (Dr. Kara Peters) %Z the Electron Imaging Center for NanoMachines supported by NIH (1S10RR23057) and the California NanoSystems Institute at UCLA %< avec comité de lecture %@ 0257-8972 %J Surface and Coatings Technology %I Elsevier %V 398 %P 126053 %8 2020-09-25 %D 2020 %R 10.1016/j.surfcoat.2020.126053 %Z Chemical Sciences/Material chemistryJournal articles %X 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. %G English %2 https://cea.hal.science/cea-02884587/document %2 https://cea.hal.science/cea-02884587/file/SURFCOAT_D_2020_Berger_V0.pdf %L cea-02884587 %U https://cea.hal.science/cea-02884587 %~ CEA %~ CNRS %~ PUBNIMBE %~ DSV %~ INC-CNRS %~ IRAMIS-NIMBE %~ CEA-UPSAY %~ UNIV-PARIS-SACLAY %~ CEA-DRF %~ TEST-HALCNRS %~ UNIVERSITE-PARIS-SACLAY %~ GS-ENGINEERING %~ IRAMIS %~ GS-CHIMIE %~ GS-PHYSIQUE %~ INSTITUT-SCIENCES-LUMIERE %~ TEST2-HALCNRS