The difficulties of nonuniform ion etching which hamper depth profiling by X-ray photoelectron spectroscopy (XPS) have been overcome by use of a mechanically scanned saddle-field ion source. The system and its calibration for uniformity are described, and its performance is illustrated by the depth profile of a Si3N4/SiO2/Si metal nitride oxide silicon device. This also allows the potential advantages of XPS profiling over Auger electron spectroscopy profiling to be discussed.
