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Characterisation of sol-gel prepared (HfO2)(x)(SiO2)(1-x) (x=0.1, 0.2 and 0.4) by H-1, C-13, O-17 and Si-29 MAS NMR, FTIR and TGA

O'Dell, Luke A. and Gunawidjaja, Philips N. and Holland, Mark A. and Mountjoy, Gavin and Pickup, Dave M. and Newport, Robert J. and Smith, Mark E. (2008) Characterisation of sol-gel prepared (HfO2)(x)(SiO2)(1-x) (x=0.1, 0.2 and 0.4) by H-1, C-13, O-17 and Si-29 MAS NMR, FTIR and TGA. Solid State Nuclear Magnetic Resonance, 33 (1-2). pp. 16-24.

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Abstract

The HfO2-SiO2 system is attracting interest as a possible new dielectric material in semiconductor devices. Knowledge of the location of hafnium within the silica network and the effect hafnium has on the structure will be central to the successful use of this material system in this application. Here, sol-gel techniques have been used to manufacture (HfO2)(x)(SiO2)(1-x) samples (x = 0.1, 0.2 and 0.4, each heat treated at 250, 500 and 750 degrees C) and these have been characterised by magic angle spinning (MAS) NMR (H-1, C-13, O-17, Si-29), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis. 29Si MAS NMR showed that increasing the hafnia content decreases the connectivity of the silicate network, i.e. increases the range of differently connected SiO4 (Q(n)) units with more having increased numbers of non-bridging oxygens (i.e. lower n). FTIR and O-17 MAS NMR showed unequivocally that the x = 0.4 sample phase-separated at higher temperatures, while in the x = 0.1 sample the hafnium was homogeneously mixed into the SiO2 phase without any phase separation. (C) 2007 Elsevier Inc. All rights reserved.

Item Type: Article
Journal or Publication Title: Solid State Nuclear Magnetic Resonance
Uncontrolled Keywords: O-17 NMR, sol-gel, nanoscale phase separation, inorganic materials
Subjects:
Departments: VC's Office
ID Code: 52862
Deposited By: ep_importer_pure
Deposited On: 29 Feb 2012 11:33
Refereed?: Yes
Published?: Published
Last Modified: 09 Apr 2014 23:10
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/52862

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