ELECTROCHEMICAL MEASUREMENTS OF INTERFACE STATES AT THE GAAS-OXIDE INTERFACE

Electrochemical measurements are used to measure the interface state density at the GaAs/oxide interface. The techniques are described, including, for example, the use of dimethyl formamide as the solvent to avoid etching the oxide. The advantages of the “EOS” meaasurement over the standard MOS measurement are outlined and demonstrated. Several advantages are realized, stemming primarily from the fact that the inert electrolyte blocks the current flow. With the MOS technique, a conducting oxide can make the interpretation very difficult. Preliminary measurements on clean and anodi-cally oxidized n- and p-type GaAs are presented. The interface state density is shown to be sensitive to anodization current programming and to low temperature annealing of the oxides. © 1979, The Electrochemical Society, Inc. All rights reserved.