Photocapacitive Determination of Spatial Distribution of Deep Levels at Si / SiO2 Interfaces

Abstract

This paper reports the results of photocapacitance measurements applied to the metal‐ SiO2‐normalSi structure. Photocapacitance measurements under a constant capacitance condition determine the spatial distribution of deep levels existing at normalSi/SiO2 interface regions. The photocapacitance method revealed deep levels distributed in a spectral region of 0.4–1.05 eV optically, and an optical level located 1.05 eV below the conduction band in the n‐ normalSi/SiO2 interface region. With respect to p‐ normalSi/SiO2 , deep levels distributed at 0.4–0.85 eV and 0.85 eV, 1.05 eV levels above the valence band, were observed. Differences of interface level densities are shown as a function of Si conduction type and different preparations of oxide layers. Comparisons with the results of capacitance‐voltage measurements are also discussed. © 1999 The Electrochemical Society. All rights reserved.