Synthesis and Characterization of Single‐Phase ReN Thin Films

Herein, a systematic study is reported on the synthesis and characterization of single‐phase rhenium nitride (ReN) thin films grown using a reactive dc magnetron sputtering (R‐dcMS). ReN thin films are expected to be superhard (bulk modulus ≈ 400 GPa) and superconducting ( T c ≈ 5 K). Since the formation enthalpy of ReN ≈ –0.14 eV is comparatively high, a stringent control of growth parameters such as partial N 2 gas flow () and growth temperature ( T s ) is necessary to achieve an impurity free and single‐phase ReN. The and the T s are systematically varied during the R‐dcMS process to find the optimal conditions for growth of ReN phase. Resulting samples are studied using X‐ray reflectivity to determine the deposition rate, density, and roughness. The crystal structure and depth profile of ReN thin films have been probed using X‐ray diffraction and secondary ion mass spectroscopy. The electronic structure is studied using hard X‐ray photoelectron spectroscopy and N K‐edge X‐ray absorption near edge structure. The superconducting transition temperature ( T c ) is found to be 3.3 K from the zero field electrical resistivity measurement. The present work constructs a phase diagram to identify the optimal conditions for forming single‐phase ReN films.