Extended x-ray absorption fine structure analysis of the difference in local structure of tantalum oxide capacitor films produced by various annealing methods

Abstract

Extended x-ray absorption fine structure (EXAFS) above the Ta L3 edge on tantalum oxide capacitor films has been measured. Tantalum oxide films were prepared by low-pressure chemical vapor deposition (CVD) using a Ta(OC2H5)5 and O2 gas mixture. Four kinds of tantalum oxide films were studied: as-deposited (amorphous), N2 annealed (crystalline), dry O2 annealed (crystalline), and O2-plasma annealed (amorphous). From EXAFS analysis, differences in the local structures of tantalum oxide capacitor films, in terms of oxygen deficiency around Ta, were observed in the various annealed films. The leakage current characteristics of tantalum oxide capacitors correspond to the differences in the local structures around Ta.

Time-resolved in situ investigations of reactive sputtering processes by grazing incidence X-ray absorption spectroscopy

“…Thus it was neglected in the present study. distance of about 2.05 Å [33,34]. However, the quality of our experimental data exhibits less noise than these studies.…”

“…However, the quality of our experimental data exhibits less noise than these studies. In addition, only a small k-range could be used for the data fitting in one of the mentioned studies [33], and the coordination numbers derived in that paper (N 1 ≈6.1 -7.8) seem to be too large, while the value for the mean square displacement σ 1 is similar to those determined here. The interatomic distance determined in the second study [34] is close to that calculated from the spectra presented here, while the value for σ 1 ≈0.1 Å is identical.…”

Electronic structure and charge transport properties of amorphous Ta2O5 films

“…Some measurements were conducted with tungsten lamp illumination. [8]. The surface morphology was further confirmed with ellipsometry measurements.…”

First principles study of oxygen vacancy migration in tantalum pentoxide

“…5 In that study, the atomistic structure of Ta 2 O 5 was chosen so that it is computationally tractable, while at the same time representative of deposited films. 7,8 In this chosen model of Ta 2 O 5 , as in deposited Ta 2 O 5 films, 7,8 the basic building blocks were TaO 6 and TaO 7 polyhedra. Based on their location, the O vacancy defects could be broadly classified into two types, each displaying qualitatively different behavior.…”