Photo-formation of interfacial layers during pulsed laser deposition of high-k dielectrics on silicon

J. M. Howard, N. D. Bassim, V. Craciun, R. K. Singh

Research output: Contribution to journalConference articlepeer-review

6 Scopus citations

Abstract

ZrO2 and Y2O3 thin films were deposited on Si substrates using pulsed laser deposition in vacuum or oxygen ambient. Angle resolved X-ray photoelectron spectroscopy investigations showed that there was always some oxidation of the Si substrate resulting in the formation of an interfacial layer that could have a deleterious effect on the overall capacitance of the resulting MOS devices. The positions and shape of the metal, the oxygen and the Si XPS peaks suggest that at the temperatures used for deposition (<650 °C) the SiO2 layer is physically mixed with the deposited oxide layer without forming silicate compounds. X-ray reflectivity investigations confirmed the presence of the interfacial layer whose density was found to be higher than that of pure SiO2 but lower than that of the corresponding silicate, corroborating the XPS results. To slow down the substrate oxidation, a low temperature UV-assisted nitridation treatment was performed prior to the deposition of the oxide layer. This UV-assisted treatment resulted in thinner and denser surface passivation layers than those obtained without any treatments indicating an incorporation of nitrogen into the SiO2 network. High-k dielectric layers deposited on such samples exhibited thinner interfacial layers.

Original languageEnglish
Pages (from-to)411-416
Number of pages6
JournalThin Solid Films
Volume453-454
DOIs
StatePublished - 1 Apr 2004
Externally publishedYes
EventProceedings of Symposium H on Photonic Processing of Surfaces - Strasbourg, France
Duration: 10 Jun 200313 Jun 2003

Keywords

  • High-k
  • Laser ablation
  • Thin films
  • Ultraviolet
  • Yttrium oxide
  • Zirconium oxide

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