Thermal stability of atomic layer deposited WCxNy electrodes for metal oxide semiconductor devices

Oren Zonensain, Sivan Fadida, Ilanit Fisher, Juwen Gao, Michal Danek, Moshe Eizenberg

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

This study is a thorough investigation of the chemical, structural, and electrical stability of W based organo-metallic films, grown by atomic layer deposition, for future use as gate electrodes in advanced metal oxide semiconductor structures. In an earlier work, we have shown that high effective work-function (4.7 eV) was produced by nitrogen enriched films (WCxNy) dominated by W-N chemical bonding, and low effective work-function (4.2 eV) was produced by hydrogen plasma resulting in WCx films dominated by W-C chemical bonding. In the current work, we observe, using x-ray diffraction analysis, phase transformation of the tungsten carbide and tungsten nitride phases after 900 °C annealing to the cubic tungsten phase. Nitrogen diffusion is also observed and is analyzed with time-of-flight secondary ion mass spectroscopy. After this 900 °C anneal, WCxNy effective work function tunability is lost and effective work-function values of 4.7-4.8 eV are measured, similar to stable effective work function values measured for PVD TiN up to 900 °C anneal. All the observed changes after annealing are discussed and correlated to the observed change in the effective work function.

Original languageEnglish
Article number035101
JournalJournal of Applied Physics
Volume123
Issue number3
DOIs
StatePublished - 21 Jan 2018
Externally publishedYes

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