Fermi level tuning using the Hf-Ni alloy system as a gate electrode in metal-oxide-semiconductor devices

Jonathan Avner Rothschild, Aya Cohen, Anna Brusilovsky, Lior Kornblum, Yaron Kauffmann, Yaron Amouyal, Moshe Eizenberg

Research output: Contribution to journalArticlepeer-review

Abstract

Hf-Ni alloys are studied as a gate electrode for metal-oxide-semiconductor devices. The Hf-Ni solid-state amorphization couple encompasses several metallurgical phenomena which are investigated at the nanoscale and are correlated with the macroscopic electrical properties of devices. The dependence of the Fermi level position on the alloy composition is studied both on SiO 2 and on HfO 2. In order to isolate the effects of interfacial and dielectric charges and dipoles, the dependence of the vacuum work-function values on the composition is also studied. The Fermi level positions of the alloys do not depend linearly on the average composition of the alloys and are strongly affected by Hf enrichment at the HfNi x/dielectric interface and the HfNi x surface. We note a constant shift of 0.4 eV in the Fermi level position on HfO 2 compared to SiO 2. In addition, characterization of the composition, structure, and morphology reveals Kirkendall voids formation when the bottom layer consists of Ni, and an oxygen-scavenging effect when the bottom layer is Hf.

Original languageEnglish
Article number013717
JournalJournal of Applied Physics
Volume112
Issue number1
DOIs
StatePublished - 1 Jul 2012

ASJC Scopus subject areas

  • General Physics and Astronomy

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