Thermal response of Ru electrodes in contact with SiO{sub 2} and Hf-based high-k gate dielectrics

Journal Article · Mon Aug 15 04:00:00 EDT 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2012510· OSTI ID:20714060

Wen, H -C; Lysaght, P; Alshareef, H N; Huffman, C; Harris, H R; Choi, K; Senzaki, Y; Luan, H; Majhi, P; Lee, B H; Campin, M J; Foran, B; Lian, G D; Kwong, D -L ^[1]

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1. SEMATECH, 2706 Montopolis Drive, Austin, Texas 78741(United States)

A systematic experimental evaluation of the thermal stability of Ru metal gate electrodes in direct contact with SiO{sub 2} and Hf-based dielectric layers was performed and correlated with electrical device measurements. The distinctly different interfacial reactions in the Ru/SiO{sub 2}, Ru/HfO{sub 2}, and Ru/HfSiO{sub x} film systems were observed through cross-sectional high-resolution transmission electron microscopy, high angle annular dark field scanning transmission electron microscopy with electron-energy-loss spectra, and energy dispersive x-ray spectra analysis. Ru interacted with SiO{sub 2}, but remained stable on HfO{sub 2} at 1000 deg. C. The onset of Ru/SiO{sub 2} interfacial interactions is identified via silicon substrate pitting possibly from Ru diffusion into the dielectric in samples exposed to a 900 deg. C/10-s anneal. The dependence of capacitor device degradation with decreasing SiO{sub 2} thickness suggests Ru diffuses through SiO{sub 2}, followed by an abrupt, rapid, nonuniform interaction of ruthenium silicide as Ru contacts the Si substrate. Local interdiffusion detected on Ru/HfSiO{sub x} samples may be due to phase separation of HfSiO{sub x} into HfO{sub 2} grains within a SiO{sub 2} matrix, suggesting that SiO{sub 2} provides a diffusion pathway for Ru. Detailed evidence consistent with a dual reaction mechanism for the Ru/SiO{sub 2} system at 1000 deg. C is presented.

• OSTI ID: 20714060
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 4 Vol. 98; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
CAPACITORS
CHEMICAL ANALYSIS
DIELECTRIC MATERIALS
ELECTRODES
HAFNIUM OXIDES
LAYERS
REACTION KINETICS
RUTHENIUM
SILICON
SILICON OXIDES
SUBSTRATES
TEMPERATURE RANGE 1000-4000 K
THICKNESS
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY SPECTRA