Zinc nitride films prepared by reactive RF magnetron sputtering of zinc in nitrogen containing atmosphere

Zinc nitride films were deposited on glass or silicon substrates by reactive magnetron RF sputtering of zinc in N2–Ar ambient. The deposition conditions were optimized in terms of substrate temperature and N2/Ar sputtering gas ratio, and representative films were then studied by structure, optical and spectroscopy techniques, and electrical measurements. Spectroscopic ellipsometry and spectrophotometry measurements revealed that the material has a direct band gap close to 1.26 eV. Hall effect and resistivity measurements indicated n-type conductivity with a very high carrier concentration of about1021 cm−3, mobility of up to 90 cm2 V−1 s−1, and resistivity of ∼10−3 Ω cm. X-ray photoelectron spectroscopy spectra clearly showed the existence of not only Zn–N bonding but also of a fraction of N–N bonding configurations, together with an oxidized surface. According to energy-dispersive x-ray spectroscopy analysis, the as-deposited films were almost stoichiometric and contained only a small fraction of oxygen.