Investigation of the oxidation behaviour of thin film and bulk copper
Abstract
Thermogravimetry (TGA) and spectroscopic ellipsometry (SE) were employed to examine the oxidation behaviour of Cu. Thermogravimetry was used to study the oxidation behaviour of bulk Cu (99.9% purity) in the range 250 to 500°C. Within this temperature range the predominant oxidation product was cupric oxide (CuO) and the reaction followed a cubic rate law. The activation energy was calculated to be 71 kJ/mol. At lower temperatures (< 150°C) spectroscopic ellipsometry was employed to characterise the oxidation kinetics of as-deposited electroless and sputtered Cu films. Analysis of the experimental spectra indicated that the rate at which the oxide grew followed an inverse logarithmic rate law. The oxidation product, which had the typical ruby red hue of cuprous oxide (Cu 2O), was confirmed as the predominant oxidation product with X-ray diffraction (XRD). The oxide scale which formed had very poor adhesion to the base material. Field emission electron microscopy (FEM) was used to examine the oxide scale topography. The low temperature product was seen to be composed of small, tightly packed grains approximately 60 nm in diameter whilst at temperatures above 300°C whisker-like crystals were also present.
- Publication:
-
Applied Surface Science
- Pub Date:
- October 1995
- DOI:
- 10.1016/0169-4332(95)00111-5
- Bibcode:
- 1995ApSS...91..152O