Influence of high power impulse magnetron sputtering plasma ionization on the microstructure of TiN thin films

Journal Article · Sun May 15 00:00:00 EDT 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3579443· OSTI ID:21560271

Ehiasarian, A P; Vetushka, A ^[1]; Gonzalvo, Y Aranda ^[2]; Safran, G; Szekely, L; Barna, P B ^[3]

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1. Nanotechnology Centre for PVD Research, Materials and Engineering Institute, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB (United Kingdom)
2. Plasma and Surface Division, Hiden Analytical Ltd., 420 Europa Boulevard, Warrington, WA5 7UN (United Kingdom)
3. Research Institute for Technical Physics and Materials Science, H-1525 Budapest, P.O. Box 49 (Hungary)

HIPIMS (High Power Impulse Magnetron Sputtering) discharge is a new PVD technology for the deposition of high-quality thin films. The deposition flux contains a high degree of metal ionization and nitrogen dissociation. The microstructure of HIPIMS-deposited nitride films is denser compared to conventional sputter technologies. However, the mechanisms acting on the microstructure, texture and properties have not been discussed in detail so far. In this study, the growth of TiN by HIPIMS of Ti in mixed Ar and N{sub 2} atmosphere has been investigated. Varying degrees of metal ionization and nitrogen dissociation were produced by increasing the peak discharge current (I{sub d}) from 5 to 30 A. The average power was maintained constant by adjusting the frequency. Mass spectrometry measurements of the deposition flux revealed a high content of ionized film-forming species, such as Ti{sup 1+}, Ti{sup 2+} and atomic nitrogen N{sup 1+}. Ti{sup 1+} ions with energies up to 50 eV were detected during the pulse with reducing energy in the pulse-off times. Langmuir probe measurements showed that the peak plasma density during the pulse was 3 x 10{sup 16} m{sup -3}. Plasma density, and ion flux ratios of N{sup 1+}: N{sub 2}{sup 1+} and Ti{sup 1+}: Ti{sup 0} increased linearly with peak current. The ratios exceeded 1 at 30 A. TiN films deposited by HIPIMS were analyzed by X-ray diffraction, and transmission electron microscopy. At high I{sub d}, N{sup 1+}: N{sub 2}{sup 1+} > 1 and Ti{sup 1+}: Ti{sup 0} > 1 were produced; a strong 002 texture was present and column boundaries in the films were atomically tight. As I{sub d} reduced and N{sup 1+}: N{sub 2}{sup 1+} and Ti{sup 1+}: Ti{sup 0} dropped below 1, the film texture switched to strong 111 with a dense structure. At very low I{sub d}, porosity between columns developed. The effects of the significant activation of the deposition flux observed in the HIPIMS discharge on the film texture, microstructure, morphology and properties are discussed.

• OSTI ID: 21560271
• Journal Information: Journal of Applied Physics, Vol. 109, Issue 10; Other Information: DOI: 10.1063/1.3579443; (c) 2011 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DISSOCIATION
IONIZATION
LANGMUIR PROBE
MAGNETRONS
MASS SPECTROSCOPY
MICROSTRUCTURE
NITROGEN
PHYSICAL VAPOR DEPOSITION
PLASMA DENSITY
POROSITY
SPUTTERING
THIN FILMS
TITANIUM IONS
TITANIUM NITRIDES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
CHARGED PARTICLES
COHERENT SCATTERING
DEPOSITION
DIFFRACTION
ELECTRIC PROBES
ELECTRON MICROSCOPY
ELECTRON TUBES
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
FILMS
IONS
MICROSCOPY
MICROWAVE EQUIPMENT
MICROWAVE TUBES
NITRIDES
NITROGEN COMPOUNDS
NONMETALS
PNICTIDES
PROBES
SCATTERING
SPECTROSCOPY
SURFACE COATING
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS