AVS 59th Annual International Symposium and Exhibition
    Thin Film Thursday Sessions
       Session TF+NS+EM-ThM

Paper TF+NS+EM-ThM12
Ion-assisted Epitaxial Sputter-Deposition and Properties of Metastable Zr1−xAlxN(001) (0.05 x 0.25 ) Alloys

Thursday, November 1, 2012, 11:40 am, Room 11

Session: Thin Films: Growth and Characterization-II
Presenter: AR.B. Mei, University of Illinois at Urbana Champaign
Authors: AR.B. Mei, University of Illinois at Urbana Champaign
B.M. Howe, University of Illinois at Urbana Champaign
N. Ghafoor, Linköping University, Sweden
E. Broitman, Linköping University, Sweden
M. Sardela, University of Illinois at Urbana Champaign
L. Hultman, Linköping University, Sweden
A. Rockett, University of Illinois at Urbana Champaign
J.E. Greene, University of Illinois at Urbana Champaign
I. Petrov, University of Illinois at Urbana Champaign
M. Oden, Linköping University, Sweden
H. Fager, Linköping University, Sweden
Correspondent: Click to Email
Single-phase epitaxial metastable Zr1-xAlxN/MgO(001) ( 0.05 x 0.25 ) thin films were deposited by ultra-high vacuum magnetically-unbalanced reactive magnetron sputtering from a single Zr0.75Al0.25target at a substrate temperature of 650°C. We control the AlN content , x , in the films by varying the ion energy ( 5 < Ei < 55 eV) incident at the film growth surface with a constant ion to metal flux ratio of 8. The net atomic flux was decreased from 3.16 to 2.45x1015 atoms cm-2s-1, due to efficient resputtering of deposited Al atoms (27 amu) by Ar+ ions (40 amu) neutralized and backscattered from heavy Zr atoms (91.2 amu). Consequentially, films varied in thickness from 400 nm to 290 nm during 20 min depositions. HfN buffer layers were deposited on the MgO(001) substrates to reduce the lattice mismatch from ~8 to ~0.5%. High resolution x-ray diffraction ω-2θ scans and reciprocal lattice mapping revealed single-phase NaCl structure with a cube-on-cube orientation relative to the substrate, (001)Zr1-x Alx N||(001)MgO, and relaxed lattice parameters varying from 4.546 with x = 0.25 to 4.598Å with x = 0.05. Film nanoindentation measurements showed that hardness decreases from 28.6 to 23.3 Gpa and Young’s modulus increases from 263 Gpa to 296.8 GP as x is varied from 0.25 to 0.05. For the same range in x, electronic transport measurements established the films to have electron mobilities increasing from 2.67 to 462 cm2V-1s-1, resistivities decreasing from 162.4 to 25.4 μΩ-cm, and positive temperature coefficients of resistivity spanning from 0.3164 to 1.307 Ω-cm K-1. Films deposited with incident ion energy above 35 eV (x< 0.08 ) exhibited superconductivity with Tc of 8.26 K.