Plasma enhanced atomic layer deposition of HfO{sub 2} and ZrO{sub 2} high-k thin films
- Department of Chemical Engineering, University of California, Los Angeles, California 90095 (United States)
A plasma enhanced atomic layer deposition (PEALD) process was developed to deposit high-k dielectric constant materials using alternative metal t-butoxide and oxygen plasma exposures. The deposited thickness increased linearly with an increasing number of precursor/oxygen plasma cycles, and the growth rates of HfO{sub 2} and ZrO{sub 2} were determined to be 1.1 and 2.8 A/cycle, respectively. The as-deposited films were determined to be fully oxidized and amorphous by the x-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared spectroscopy (FTIR). The PEALD films were found to have high concentrations of bridging oxygen bonds with metals (M-O-M) as the film thickness increased, in contrast to the high concentrations of M-O-H in the films deposited by plasma enhanced chemical vapor deposition (PECVD). The M-O-M bonds in the PEALD films were further increased upon annealing at 250 deg. C in atmosphere with a corresponding decrease in M-O-H concentrations, suggesting the elimination of hydroxyl groups upon annealing. The PEALD HfO{sub 2} and ZrO{sub 2} films showed higher dielectric constants (25, 22) than those of PECVD deposited films (21, 19), likely due to the enhanced ionic contribution from the M-O-M bonds in the PEALD films. The smallest equivalent oxide thickness (EOT) of 13 A was achieved by PEALD HfO{sub 2} with a leakage current density of 0.2 A/cm{sup 2}, several orders of magnitude below that of thermally grown SiO{sub 2} films with the same EOT.
- OSTI ID:
- 20637092
- Journal Information:
- Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Vol. 23, Issue 3; Other Information: DOI: 10.1116/1.1894666; (c) 2005 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0734-2101
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
CHEMICAL VAPOR DEPOSITION
FOURIER TRANSFORM SPECTROMETERS
HAFNIUM OXIDES
HYDROXYL RADICALS
INFRARED SPECTRA
LEAKAGE CURRENT
OXYGEN
PERMITTIVITY
PLASMA
SILICON OXIDES
THICKNESS
THIN FILMS
X-RAY PHOTOELECTRON SPECTROSCOPY
ZIRCONIUM OXIDES