ISSN:
0142-2421
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Physics
Notes:
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 Ta2O5 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 SiO2 and Al2O3 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 SiO2 surface to form Ta2O5. 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 Ta2O5. X-ray photoelectron spectroscopy was also used to show that the oxide layer slowly increases in thickness when heated in air. Finally, KTaO3 was identified by XANES on the surface of films exposed to KOH. Once the passive Ta2O5 is converted to KTaO3, further oxidation of the underlying films occurs. The mechanism of oxidation of these films and the unique advantages of each spectroscopic technique are discussed.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/sia.740200703
