| Crystal Research and Technology |
The method of the electrochemical profiling was used to measure depth profiles of carrier concentration in multilayer structures of n-type GaAs grown by molecular beam epitaxy. Tiron or HCl aqueous solution diluted with methanol was applied to form Schottky barriers between the semiconductor and electrolyte and to remove controlled amounts of material by electrochemical etching. A discrepancy between the intended and observed profiles has been interpreted as a result of electrochemically etched tunnels in GaAs. Our results indicate that the existence of the so-called oval defects, which are typical defects for the epitaxial growth, should be considered as a reason of difficulties in measuring carrier profiles. In the presence of the oval defects very careful optimisation of measuring conditions is necessary for obtaining reliable results. The usefulness of the HCl solution that is rather occasionally used as the electrolyte for the electrochemical profiling of an GaAs, is confirmed.
Keywords: GaAs, electrochemical C-V profiling, electrolyte barriers, oval defects
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