Thermal decomposition mechanisms of hafnium and zirconium silicates at the atomic scale
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Date
2005-06-01
Authors
Monaghan, Scott
Greer, James C.
Elliott, Simon D.
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Publisher
AIP Publishing
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Abstract
The hafnium and zirconium silicates, (MO2)(x)(SiO2)(1-x), with M=Hf/Zr, are being considered as high-k gate dielectrics for field-effect transistors as a compromise between high permittivity and thermal stability during processing. Using atomic-scale models of silicates derived from hafnon/zircon, stability before and after simulated thermal annealing is calculated within a density-functional approach. These silicates are found to be thermodynamically unstable with respect to decomposition into SiO2 and MO2 (M=Hf/Zr). Segregation mechanisms on the atomic scale are studied leading to an insight as to an why SiO2-rich mixtures undergo spinodal decomposition and why, by contrast, MO2-rich phases are metastable, decomposing below typical process temperatures.
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Keywords
Total-energy calculations , Wave basis-set , Gate dielectrics , Phase-separation , Transition , Dioxide , Diagram , Alloys , Films , Oxide , Zircon , Annealing , Amorphous state , Silica , Crystal structure
Citation
Monaghan, S., Greer, J. C. and Elliott, S. D. (2005) 'Thermal decomposition mechanisms of hafnium and zirconium silicates at the atomic scale', Journal of Applied Physics, 97(11), pp. 114911. doi: 10.1063/1.1926399
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© 2005 American Institute of Physics, This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Monaghan, S., Greer, J. C. and Elliott, S. D. (2005) 'Thermal decomposition mechanisms of hafnium and zirconium silicates at the atomic scale', Journal of Applied Physics, 97(11), pp. 114911 and may be found at http://aip.scitation.org/doi/abs/10.1063/1.1926399