Kenji Ishikawa, Tatsuo Ishijima, et al.
Japanese Journal of Applied Physics
In situ x-ray photoelectron spectroscopy (XPS), etch rate measurements, and optical emission spectroscopy have been used to examine the etching characteristics of tungsten in CF4/O2 reactive ion etching plasmas. It is found that the etch rate maximum of tungsten occurs at a proportion of oxygen in excess of that required to produce the maximum gas phase fluorine atom concentration, and this cannot be explained by using an etch mechanism model similar to that developed for silicon. XPS results have been used to identify tungsten oxyfluoride (WOF4) on the etched surface, and a model for tungsten etching is proposed that involves tungsten oxyfluoride as an important etch product.
Kenji Ishikawa, Tatsuo Ishijima, et al.
Japanese Journal of Applied Physics
David Angell, Gottlieb S. Oehrlein
Applied Physics Letters
Ying Zhang, Gottlieb S. Oehrlein, et al.
Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Gottlieb S. Oehrlein, Holly L. Williams
Journal of Applied Physics