Impact of titanium addition on film characteristics of HfO{sub 2} gate dielectrics deposited by atomic layer deposition

Journal Article · Thu Sep 01 00:00:00 EDT 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2030407· OSTI ID:20714090

Triyoso, D H; Hegde, R I; Zollner, S; Ramon, M E; Kalpat, S; Gregory, R; Wang, X -D; Jiang, J; Raymond, M; Rai, R; Werho, D; Roan, D; White, Jr, B E; Tobin, P J ^[1]

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1. Freescale Semiconductor, Inc., Advanced Products Research and Development Laboratory, 3501 Ed Bluestein Boulevard, Austin, Texas 78721 (United States)

The impact of 8-to 45-at. % Ti on physical and electrical characteristics of atomic-layer-deposited and annealed hafnium dioxide was studied using vacuum-ultraviolet spectroscopic ellipsometry, secondary ion mass spectroscopy, transmission electron microscopy, atomic force microscopy, x-ray diffraction, Rutherford backscattering spectroscopy, x-ray photoelectron spectroscopy, and x-ray reflectometry. The role of Ti addition on the electrical performance is investigated using molybdenum (Mo)-gated capacitors. The film density decreases with increasing Ti addition. Ti addition stabilizes the amorphous phase of HfO{sub 2}, resulting in amorphous films as deposited. After a high-temperature annealing, the films transition from an amorphous to a polycrystalline phase. Orthorhombic Hf-Ti-O peaks are detected in polycrystalline films containing 33-at. % or higher Ti content. As Ti content is decreased, monoclinic HfO{sub 2} becomes the predominant microstructure. No TiSi is formed at the dielectric/Si interface, indicating films with good thermal stability. The band gap of Hf-Ti-O was found to be lower than that of HfO{sub 2}. Well-behaved capacitance-voltage and leakage current density-voltage characteristics were obtained for Hf-Ti-O. However, an increased leakage current density was observed with Ti addition. The data from capacitance-voltage stressing indicate a smaller flatband voltage (V{sub fb}) shift in the HfO{sub 2} films with low Ti content when compared with the HfO{sub 2} films. This indicates less charge trapping with a small amount of Ti addition.

• OSTI ID: 20714090
• Journal Information: Journal of Applied Physics, Vol. 98, Issue 5; Other Information: DOI: 10.1063/1.2030407; (c) 2005 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
AMORPHOUS STATE
ANNEALING
ATOMIC FORCE MICROSCOPY
CAPACITANCE
DIELECTRIC MATERIALS
ELECTRIC POTENTIAL
ELLIPSOMETRY
HAFNIUM OXIDES
ION MICROPROBE ANALYSIS
MASS SPECTROSCOPY
MOLYBDENUM
MONOCLINIC LATTICES
RUTHERFORD BACKSCATTERING SPECTROSCOPY
TITANIUM ADDITIONS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY