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Characterization of the oxidation of tantalum nitride
Author(s) -
Ibidunni A. O.,
Masaitis R. L.,
Opila R. L.,
Davenport A. J.,
Isaacs H. S.,
Taylor J. A.
Publication year - 1993
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740200703
Subject(s) - x ray photoelectron spectroscopy , auger electron spectroscopy , xanes , tantalum , tantalum nitride , analytical chemistry (journal) , thin film , absorption spectroscopy , nitride , materials science , sputtering , electron spectroscopy , absorption (acoustics) , spectroscopy , chemistry , layer (electronics) , chemical engineering , nanotechnology , optics , metallurgy , composite material , physics , chromatography , quantum mechanics , nuclear physics , engineering
Sputter‐deposited non‐stoichiometric tantalum nitride films are used for laser‐trimmed thin‐film resistors owing to their stability and processability. The films are stabilized by heating in air to form a passive Ta 2 O 5 film. This passive film can be destroyed if the resistors are exposed to aggressive thermal or chemical conditions. Thus we have studied sputtered TaN films and resistors deposited on SiO 2 and Al 2 O 3 substrates and exposed to either KOH solutions or air at 250–500 °C for various times. The oxidized films have been characterized with Auger electron spectroscopy (AES), x‐ray photelectron spectroscopy (XPS), x‐ray absorption near‐edge spectroscopy (XANES) and extended x‐ray absorption fine structure (EXAFS). Chemical shifts in the NOO Auger spectrum have been used to show that the initial fraction of deposited TaN reacts with the SiO 2 surface to form Ta 2 O 5 . X‐ray photoelectron spectroscopy showed that although significant amounts of oxygen can be present in the sputered films, little of the tantalum is fully oxidized to Ta 2 O 5 . X‐ray photoelectron spectroscopy was also used to show that the oxide layer slowly increases in thickness when heated in air. Finally, KTaO 3 was identified by XANES on the surface of films exposed to KOH. Once the passive Ta 2 O 5 is converted to KTaO 3 , further oxidation of the underlying films occurs. The mechanism of oxidation of these films and the unique advantages of each spectroscopic technique are discussed.