Sub-micron ZnO:N particles fabricated by low voltage electrical discharge lithography on Zn3N2 sputtered films

• Published in: Applied surface science 2013-11, Vol.285, p.783-788
• Main Authors: Núñez, C. García, Jiménez-Trillo, J., Vélez, M. García, Piqueras, J., Pau, J.L., Coya, C., Álvarez, A.L.
• Format: Article
• Language: English
• Subjects: Arc discharge lithography; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Magnetron sputtering; Microfabrication; Physics; Zinc nitride; Zinc oxide
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2013.08.129

•Arc discharge lithography produced by a metal tip was used to modify Zn3N2 thin films.•Properties of resultant layers were examined by SEM, IBA and resistivity measurements.•At higher voltage discharges, IBA confirmed Zn3N2 was transformed into ZnO:N crystals.•Dimensions of submicron ZnO:N crystals was similar than initial Zn3N2 grain domains.•Different stoichiometry between ZnO and Zn3N2 formed Zn droplets along the scan edges. This work analyzes the morphological, compositional and electrical modification of zinc nitride (Zn3N2) films through arc discharges produced by biasing a metal tip at a micrometric distance of the surface. Polycrystalline nitride layers are prepared by radio-frequency magnetron sputtering from a pure Zn target on glass substrates using N2 as working gas. Film properties after arc discharges are investigated by using scanning electron microscopy (SEM), ion beam analysis (IBA) techniques and four-probe resistivity measurements. Electrical discharge lithography performed at low bias voltages reveals as an effective mechanism to reduce resistivity by electrical breakdown of the thin oxide layer formed on top of the nitride. At higher voltages, electrical discharges along the scan increase nitride resistivity due to the severe modification of the structural properties. Additionally, compositional analysis reveals that nitrogen leaves the structure being replaced by ambient oxygen. This characteristic behavior leads to the formation of facetted submicron ZnO crystals whose size depends on the original Zn3N2 grain size and the probe voltage used. The excess of zinc forms self-assembled microstructures along the scan edge.