Band alignments of higii-k dielectrics on Si and Pt

J. Robertson, E. Riassi, Jon-Paul Maria, A. I. Kingon

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Materials with a high dielectric constant (K) such as tantalum pentoxide (Ta2O5) and barium strontium titanate (BST) are needed for insulators in dynamic random access memory capacitors and as gate dielectrics in future silicon devices. The band offsets of these oxides must be over 1 eV for both electrons and holes, to minimise leakage currents due to Schottky emission. We have calculated the band alignments of many high K materials on Si and metals using the method of charge neutrality levels. Ta2O5 and BST have rather small conduction band offsets on Si, because the band alignments are quite asymmetric. Other wide gap materials Al2O3, Y2O3, ZrO2 and ZrSiO4 are found to have offsets of over 1.5 eV for both electrons and holes, suggesting that these are preferable dielectrics. Zirconates such as BaZrO3 have wider gaps than the titanates, but they still have rather low conduction band offsets on Si. The implications of the results for future generations of MOSFETs and DRAMS are discussed.

Original languageEnglish (US)
Pages (from-to)87-92
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume592
StatePublished - Dec 1 2000

Fingerprint

Barium strontium titanate
alignment
Conduction bands
strontium
barium
conduction bands
zirconates
titanates
Electrons
Gate dielectrics
random access memory
Tantalum
Silicon
tantalum
Leakage currents
Oxides
capacitors
Capacitors
leakage
electrons

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Robertson, J. ; Riassi, E. ; Maria, Jon-Paul ; Kingon, A. I. / Band alignments of higii-k dielectrics on Si and Pt. In: Materials Research Society Symposium - Proceedings. 2000 ; Vol. 592. pp. 87-92.
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Band alignments of higii-k dielectrics on Si and Pt. / Robertson, J.; Riassi, E.; Maria, Jon-Paul; Kingon, A. I.

In: Materials Research Society Symposium - Proceedings, Vol. 592, 01.12.2000, p. 87-92.

Research output: Contribution to journalArticle

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AU - Maria, Jon-Paul

AU - Kingon, A. I.

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AB - Materials with a high dielectric constant (K) such as tantalum pentoxide (Ta2O5) and barium strontium titanate (BST) are needed for insulators in dynamic random access memory capacitors and as gate dielectrics in future silicon devices. The band offsets of these oxides must be over 1 eV for both electrons and holes, to minimise leakage currents due to Schottky emission. We have calculated the band alignments of many high K materials on Si and metals using the method of charge neutrality levels. Ta2O5 and BST have rather small conduction band offsets on Si, because the band alignments are quite asymmetric. Other wide gap materials Al2O3, Y2O3, ZrO2 and ZrSiO4 are found to have offsets of over 1.5 eV for both electrons and holes, suggesting that these are preferable dielectrics. Zirconates such as BaZrO3 have wider gaps than the titanates, but they still have rather low conduction band offsets on Si. The implications of the results for future generations of MOSFETs and DRAMS are discussed.

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