IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Thin Films Friday Sessions
       Session TF-FrM

Paper TF-FrM5
Influence of Nitrogen and Temperature on the Deposition of Fluorinated Amorphous Carbon Films

Friday, November 2, 2001, 9:40 am, Room 123

Session: Diamond and Related Materials
Presenter: L. Valentini, Universita di Perugia, Italy
Authors: L. Valentini, Universita di Perugia, Italy
E. Braca, Universita di Perugia, Italy
J. Kenny, Universita di Perugia, Italy
R.M. Montereali, Dip. Innovazione ENEA C.R. Frascati, Italy
L. Lozzi, Universita dell'Aquila, Italy
S. Santucci, Universita dell'Aquila, Italy
Correspondent: Click to Email
Plasma deposited hydrogenated amorphous (a-C:H) carbon and fluorinated amorphous carbon films (a-C:H:F) are among the potential candidates considered for the low dielectric constant (k) interconnects. Incorporation of the low-k materials in ULSI integrated structures imposes a lot of requirements to be satisfied, among them stability at the processing temperature of 400°C. As deposited a-C:H:F films may be thermally stabilised, in terms of dimensional stability and material loss, by nitrogen incorporation. In this work the effect of nitrogen addition on the properties of a-C:H:F films produced by radio-frequency plasma enhanced chemical vapor deposition has been investigated. The films were studied as a function of nitrogen content and deposition temperature. The structural and optical properties were investigated by x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV-VIS transmittance and ellipsometry measurements. The dependence of both fluorine and nitrogen incorporation in the carbon matrix on deposition temperature has been analysed. It was found that the main effect of progressive nitrogen incorporation is a decrease of transmittance and optical band gap of the samples grown at room temperature and at 400°C. Raman spectra evidence that for films deposited at 400°C a sudden loss of sp3 carbon bonding occurs. In particular, at fixed plasma composition the decrease of the optical band gap is interpreted as a clustering of the existing sp2 carbon sites. The ellipsometry characterization indicates that nitrogen incorporation for the room temperature deposited samples induces an increase of the refractive index and suggested that carrying out a deposition at 400°C the films undergo a reduction of the refractive index; this has been correlated to changes in the graphitic cluster size of the network. In particular the increase in the deposition temperature produces an increase in the size of the graphitic clusters.