Sputter Crater Contour Mapping with Multilayered Films

Authors

L. L. Levenson, University of Colorado, Colorado Springs
T. P. Massopust, Solar Energy Research Institute
J. Dick, Solar Energy Research Institute
M. C. Jaehnig, Montana State University
D. Griffith, Hewlett-Packard Corporation

Abstract

Multilayered films composed of alternating 200 Å Al and 267 Å Al203 layers are made by physical vapor deposition. Twenty-two pairs of these films are deposited on a polished Si wafer. Ion beam sputtering is used to form craters in the multilayered film. When a crater is viewed or photographed in situ by scanning electron microscopy, the Al₂O₃ layers appear bright and the Al layers appear dark. In the scanning electron microscope (SEM) the Al₂O₃ layers have a high secondary electron yield compared to Al. In secondary ion mass spectrometry (SIMS), using Cs⁺ as the ion beam, imaging with O^- produces an image with Al₂O₃ layers appearing white and with Al layers appearing dark. Scanning Auger microscopy (SAM) imaging of oxygen produces the same result. In all cases, the alternating bright and dark layers along the wall of the sputter crater form a contour map. The width of each bright band represents a change of depth corresponding to the thickness of the Al₂O₃ layer and similarly for the dark Al bands. Therefore, the operator of a SEM, SAM or SIMS unit can determine the depth as well as the shape of a sputter crater in situ by using a multilayered film. The main requirement is that the films be smooth on a scale that is small compared to the thickness of each layer and that alternate films have high contrast in the imaging process.

Recommended Citation

Levenson, L. L.; Massopust, T. P.; Dick, J.; Jaehnig, M. C.; and Griffith, D. (1985) "Sputter Crater Contour Mapping with Multilayered Films," Scanning Electron Microscopy: Vol. 1985: No. 3, Article 17.
Available at: https://digitalcommons.usu.edu/electron/vol1985/iss3/17