Study of Hf-Al-O high-k gate dielectric thin films grown on Si

P. F. Lee, J. Y. Dai, H. L.W. Chan, C. L. Choy

Research output: Journal article publicationJournal articleAcademic researchpeer-review

4 Citations (Scopus)


Ultrathin amorphous films of Hf-aluminate (Hf-Al-O) have been deposited on p-type (100) Si substrates by pulsed-laser deposition. Transmission electron microscopy study revealed that for the films deposited in oxygen ambient with partial pressure of 1 × 10-3Pa, the amorphous structure of Hf-Al-O films is stable under rapid thermal annealing at temperatures up to at least 1000°C. Electrical properties have been characterized by means of high-frequency capacitance-voltage measurements at 1 MHz on the metal-oxide-semiconductor (MOS) capacitors using Pt dot electrode. The relative permittivity of the Hf-Al-O dielectric film is calculated approximately to be about 10 and the equivalent oxide thickness to SiO2is 30 Å. However, for the Hf-Al-O films deposited in a relatively higher vacuum condition (1 × 10-4Pa), islands of Hf suicide formed from interfacial reaction between the films and Si substrates. The formation of Hf suicide was attributed to the presence of Al oxide in the films that altered the Gibbs free energy for the reaction between the Hf atoms in the amorphous Hf-Al-O films and Si under an oxygen deficient condition. X-ray photoelectron spectroscope results suggested that there is Hf suicide formation in the interfacial region.
Original languageEnglish
Pages (from-to)1213-1219
Number of pages7
JournalIntegrated Ferroelectrics
Publication statusPublished - 1 Dec 2003


  • Hf-Al-O
  • High-k gate dielectric
  • MOS
  • Pulsed-laser deposition

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering

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