Plasma-enhanced atomic layer deposition of titanium molybdenum nitride: Influence of RF bias and substrate structure

Md Istiaque Chowdhury, Mark Sowa, Kylie E. Van Meter, Tomas F. Babuska, Tomas Grejtak, Alexander C. Kozen, Brandon A. Krick, Nicholas C. Strandwitz

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1 Scopus citations

Abstract

In this work, TiMoN thin films were deposited by plasma-enhanced atomic layer deposition with an equal number of Ti and Mo precursor exposures at a substrate temperature of 250 °C. Tetrakis(dimethylamido) titanium and bis(tert-butylimido)bis(dimethylamido) molybdenum were used as sources for Ti and Mo, respectively. N2 and N2/H2 plasma were used, respectively, for TiN and MoN cycles as a source for N. Negative RF substrate bias voltage of magnitude, |Vbias|, of 0, 31, 62, 125, and 188 V were applied during the plasma half cycle. Nanocrystalline rock salt crystal structures were found by x-ray diffraction for films deposited on single-crystal Si and Si-thermal oxide substrates. Applying |Vbias| generated voids by the bombardment of high-energy ions, lowering the density. Further increase of |Vbias| caused the annihilation of voids and a slight increase in density. Four-point probe measurement showed increased electrical resistivity due to a reduction in grain size caused by continuous renucleation during growth. High-energy ions at high |Vbias| sputtered away the films resulting in low growth rates. Stripe test revealed inferior wear rates and coefficients of friction at higher |Vbias| due to low-density porous films. Epitaxial films deposited on c-plane sapphire had (111) orientation and considerable mosaicity with twinned domains rotated at 60° to each other.

Original languageEnglish
Article number053408
JournalJournal of Vacuum Science and Technology, Part A: Vacuum, Surfaces and Films
Volume39
Issue number5
DOIs
StatePublished - Sep 1 2021
Externally publishedYes

Funding

All the authors acknowledge the National Science Foundation for funding this research through Project NSF No. CMMI #1826251. This material is based on work supported by the National Science Foundation Graduate Research Fellowship Program under Grant Nos. 1449440 (K.E.V.M.) and 1842163 (T.F.B.). TEM work was carried out by Dr. Yan Xin at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement No. DMR-1644779, and the State of Florida.

FundersFunder number
State of Florida
National Science FoundationDMR-1644779, 1826251, 1449440, 1842163

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