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Atomic Layer Deposition of Nickel Nitride Thin Films using NiCl 2 (TMPDA) and Tert‐Butylhydrazine as Precursors
Author(s) -
Väyrynen Katja,
Hatanpää Timo,
Mattinen Miika,
Heikkilä Mikko J.,
Mizohata Kenichiro,
Räisänen Jyrki,
Link Joosep,
Stern Raivo,
Ritala Mikko,
Leskelä Markku
Publication year - 2019
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201900058
Subject(s) - materials science , crystallinity , nickel , nitride , electrical resistivity and conductivity , atomic layer deposition , stoichiometry , metal , thin film , nitrogen , layer (electronics) , chemical vapor deposition , analytical chemistry (journal) , inorganic chemistry , chemical engineering , metallurgy , nanotechnology , chemistry , composite material , organic chemistry , engineering , electrical engineering
This article describes the atomic layer deposition (ALD) of nickel nitride and nickel thin films using a diamine adduct of Ni(II) chloride, NiCl 2 (TMPDA) (TMPDA = N,N,N′,N′, ‐tetramethyl‐1,3‐propanediamine), as the metal precursor. Owing to the high reducing power of tert‐butylhydrazine (TBH), the films are grown at low temperatures of 190–250 °C. This is one of the few low‐temperature ALD processes that can be used to grow Ni 3 N and Ni metal on both insulating and conductive substrates. The films are characterized in terms of crystallinity, morphology, composition, resistivity, and coercivity. X‐ray diffraction shows reflections compatible with either hexagonal Ni or Ni 3 N. Composition analyses suggest that the films are close to stoichiometric Ni 3 N. Despite the nitride component, the films exhibit low resistivity values and at the lowest, a resistivity of 37 μΩ cm is achieved. The result is lower than what is typically observed for Ni x N films and not much higher than the best results concerning ALD Ni metal. The nitrogen content of the films is lowered down to 1.2 at% by postdeposition reduction at 150 °C in 10% forming gas. After the reduction, the nonmagnetic nitride films are converted to ferromagnetic Ni metal.