EPR characterization of defects in monoclinic powders of ZrO2 and HfO2

✍ Scribed by Sandra Wright; R.C. Barklie

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 231 KB
• Volume: 9
• Category: Article
• ISSN: 1369-8001
• DOI: 10.1016/j.mssp.2006.10.006

✦ Synopsis

Electron paramagnetic resonance (EPR) measurements have been made on a variety of commercially available samples of the monoclinic form of the high-dielectric constant (high k) materials ZrO 2 and HfO 2 with the aim of characterizing the defects they contain. All EPR measurements were at about 9.5 GHz and at room temperature. An axially symmetric spectrum with g k ¼ 1:961ð2Þ, g ? ¼ 1:976ð2Þ is observed in most of the ZrO 2 samples and a similar one with g k ¼ 1:940ð3Þ, g ? ¼ 1:970ð2Þ is seen for most of the HfO 2 samples; they are attributed to centres involving Zr 3+ and Hf 3+ , respectively. Their average concentration lies in the approximate range 10 15 -10 17 cm À3 , depending on the product specification, and, with one exception is unaffected by g-irradiation. Grinding granules to powder and/or g-irradiation yields further EPR spectra of defects, some of which are likely to involve oxygen, those are probably in the near surface region.