| Abstrakt: |
Electroreflectance is applied to study the interface properties of metal/SiO2/GaAs structures. From a bias-voltage dependence of surface potential, which was evaluated from the measured surface field in i/n+-GaAs structures, energy distributions of interface-state density were determined based on the modulation spectroscopy technique. Upon biasing toward inversion, a strong pinning of surface Fermi level occurred at around 0.88 eV below the conduction-band minimum. This pinning, thus, is concluded to be due to a large number of interface states, and not due to an actual hole inversion. The method is free from numerical ambiguities encountered in capacitance-based techniques, in which the energy reference for surface Fermi level is model dependent, and thus, is a suitable tool for studying insulator/semiconductor interfaces, even having a large number of interface traps. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR] |
