conduction band potential obtained from the threshold measurements shows only a small deviation from a fiat band, less than โข i 0.05 eV, tip to a point 4 A, from the silicon surface. There is no indication of a large ionic charge or of a greatly reduced SiO, bandgap to within about two lattice units of the interface. T H DiStefano, J Vac Sci Technol, 13 (4), 1976, 856-859. 36 2504. Auger depth profiling of interfaces in MOS and MNOS structures. (USA) Auger electron spectroscopy in conjunction with simultaneous Argon-ion sputtering have been used in a study of the chemical depth profiles of the near-interface regions in MOS and MNOS device structures. Our experimental results show that all these interfaces are nonabrnpt and phase separated. The AI-SiO, inlerface has inclusions of Si and AI_,O3; the SiO.,-Si interface appears to be a mixed phase of Si and SiO., over several nanometers and the nitrideoxide interface is an oxynitride. The width of these interfaces varies from 35 to several hundred angstrom, depending on the deposition technique and on the deposition conditions. The inherent limitations in the depth resolution of Auger/sputter profiling are discussed in some detail. We also describe the precautions we have taken to minimize electron and ion beam induced distortion of the Auger spectra and the depth profiles.