https://doi.org/10.1051/epjap:2005067
Effect of nitrogen addition on the properties of C:F thin films deposited by RF sputtering
Laboratory for Electrostatics and Dielectric Materials (LEMD),
French National Centre for Scientific Research (CNRS) and Joseph Fourier
University (UJF),
LEMD-CNRS, BP 166, 38042 Grenoble Cedex 9, France
Corresponding author: patrice.gonon@grenoble.cnrs.fr
Received:
14
December
2004
Revised:
29
March
2005
Accepted:
24
June
2005
Published online:
25
October
2005
Fluorocarbon (C:F) and nitrogen-doped fluorocarbon (C:F:N) thin films are deposited by RF magnetron sputtering using a polytetrafluoroethylene (PTFE) target and Ar or Ar/N2 sputtering gas. Properties of C:F:N films are compared to those of C:F films. They are studied using X-ray Photoelectron Spectroscopy (XPS), Infra-Red (IR) transmission spectroscopy, Thermo-Gravimetric Analysis (TGA), impedance spectroscopy, and current-voltage measurements. By adding nitrogen to the sputtering gas, XPS shows that nitrogen substitutes for fluorine leading to a decrease in the relative concentration of CFx species, to an increase in C-C bonds, and to the appearance of specific CFN bonds. There is also a new IR band at 1350 cm-1 whose origin is uncertain (CN bonds or disordered sp2 carbon). Thermal stability is not improved upon nitrogen addition (the C:F and C:F:N films both decompose above 200 °C). Dielectric properties (dielectric constant and loss) are only slightly affected by nitrogen doping. The DC transport properties are modified upon nitrogen addition (C:F:N films display a higher resistivity and a supra-linear behaviour at high fields indicative of field-enhanced tunnelling transport).
PACS: 77.55.+f – Dielectric thin films / 73.61.-r – Electrical properties of specific thin films / 68.60.-p – Physical properties of thin films, nonelectronic
© EDP Sciences, 2005