Substrate biasing effect on the electrical properties of magnetron-sputtered high-k titanium silicate thin films

Journal Article · Wed Aug 01 00:00:00 EDT 2007 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2759196· OSTI ID:21057477

Brassard, D; El Khakani, M A; Ouellet, L ^[1]

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1. Institut National de la Recherche Scientifique, INRS-Energie, Materiaux et Telecommunications, 1650 Boulevard Lionel-Boulet, Case Postale 1020, Varennes, Quebec J3X 1S2 (Canada)

We report on the effect of substrate biasing on the properties of high-dielectric constant (high-k) titanium silicate (Ti{sub x}Si{sub 1-x}O{sub 2}) thin films deposited with a room-temperature magnetron-sputtering process. The composition, microstructure, and electrical properties of the Ti{sub x}Si{sub 1-x}O{sub 2} films were systematically characterized, as a function of the substrate bias voltage (V{sub S}), by means of various complementary techniques, including x-ray photoelectron spectroscopy, x-ray reflectivity, Rutherford backscattering spectrometry, and appropriate electrical characterizations. We show, in particular, that depositing the Ti{sub x}Si{sub 1-x}O{sub 2} films with a relatively small biasing voltage (V{sub S}{approx_equal}-15 V) leads not only to a significant reduction of their porosity but more interestingly to a marked improvement of their electrical properties. A further increase of the negative bias voltage (from 20 to 110 V) was, however, found to increase progressively the leakage current through the Ti{sub x}Si{sub 1-x}O{sub 2} films. Such a degradation of the electrical properties at high V{sub S} values is shown to be associated with some resputtering and defects generation caused by the rather energetic bombardment conditions. In contrast, the 'soft hammering' induced by the relatively low-energy ion bombardment densifies the films and improves their properties. Under the optimal substrate biasing conditions (V{sub S}{approx}-15 V), the room-temperature deposited titanium silicate films are shown to exhibit a highly attractive combination of electrical properties, namely a k value as high as {approx}17, a dissipation factor <0.01, a leakage current as low as 5x10{sup -9} A/cm{sup 2} at 1 MV/cm, and a breakdown field higher than 4 MV/cm.

• OSTI ID: 21057477
• Journal Information: Journal of Applied Physics, Vol. 102, Issue 3; Other Information: DOI: 10.1063/1.2759196; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DEPOSITION
DIELECTRIC MATERIALS
DISSIPATION FACTOR
ELECTRIC POTENTIAL
ION BEAMS
LEAKAGE CURRENT
MAGNETRONS
MICROSTRUCTURE
PERMITTIVITY
POROSITY
REFLECTIVITY
RUTHERFORD BACKSCATTERING SPECTROSCOPY
SPUTTERING
SUBSTRATES
TEMPERATURE RANGE 0273-0400 K
THIN FILMS
TITANIUM SILICATES
X-RAY PHOTOELECTRON SPECTROSCOPY