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Sputter Deposition of Transition Metal Oxides on Silicon: Evidencing the Role of Oxygen Bombardment for Fermi‐Level Pinning
Author(s) -
Poulain Raphaël,
Proost Joris,
Klein Andreas
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.201900730
Subject(s) - sputtering , materials science , x ray photoelectron spectroscopy , silicon , non blocking i/o , oxygen , sputter deposition , oxide , analytical chemistry (journal) , layer (electronics) , transition metal , thin film , metallurgy , chemistry , chemical engineering , nanotechnology , biochemistry , organic chemistry , chromatography , engineering , catalysis
Different magnetron sputtering‐based deposition methods of nickel oxide SiO 2 ‐passivated Si surfaces are compared. Results highlight that the presence of oxygen in the deposition chamber during reactive sputtering drastically affects the Si/SiO 2 interface. An alternative method for the preparation of NiO is the sputtering of metallic nickel in oxygen‐free atmosphere followed by a post oxidation of the deposited layer in an oxygen atmosphere without plasma exposition is proposed. This method is introduced as metal layer oxidation (MLO). Using this technique, the barrier height on n‐type silicon increases from ≈0.4 eV for reactively sputtered NiO to more than 0.6 eV for the MLO method. In situ photoelectron spectroscopy evidences the formation of an extra electronic state when NiO is reactively sputtered, which is assigned to the intense oxygen ion bombardment of the Si/SiO 2 surface during the process. This extra‐electronic state pins the silicon energy bands in an undesirable position. The extra‐electronic state is associated with oxygen interstitial in the SiO 2 implanted during reactive sputtering.