Synthesis of nanocrystalline δ-MoN by thermal annealing of amorphous thin films grown on (100) Si by reactive sputtering at room temperature

Publication date: 30 August 2018
Source:Thin Solid Films, Volume 660
Author(s): N. Haberkorn, S. Bengio, H. Troiani, S. Suárez, P.D. Pérez, M. Sirena, J. Guimpel
We report on the synthesis and characterization of nanocrystalline δ-MoN by crystallization of amorphous thin films grown on (100) Si by reactive sputtering at room temperature. Films with chemical composition MoN were grown using a deposition pressure of 5mTorr with a reactive mixture of Ar/(Ar + N2) = 0.5. The as-grown films display mostly amorphous structure. Nanocrystalline δ-MoN phase is obtained after annealing at temperatures above 600 °C. The superconducting critical temperature T c depends on film thickness. Thick films (170 nm) annealed at 700 °C for 30 min display a T c  = 11.2 K (close to the one reported for bulk specimens: 13 K), which is gradually suppressed to 7.2 K for 40 nm thick δ-MoN films. Our results provide a simple method to synthesize superconducting nitride thin films on silicon wafers with T c above the ones observed for conventional superconductors such as Nb.