Electrochemical Etching and CV-Profiling of GaN

Abstract

We report on the implementation of a robust and reproducible electrochemical CV (ECV) characterization for the (Al, In)GaN material system. A Schottky-like contact is formed by electrolyte, wetting the area of the semiconductor surface delimited by a sealing ring. In reverse bias with common CV technique the concentration of donors and acceptors can be evaluated. Using a newly developed etch procedure, which we call “cyclic oxidation”, n- and p-type nitrides can be etched (photo-)electrochemically (PEC) to yield reproducibly etched surfaces with mirror-like surface morphology at high etch rates (∼3 μm/h). This new etch procedure is explained in detail. The influence of the process parameters on the etch rate is discussed. Using this new etch procedure, various MOVPE and HVPE grown samples have been characterized by CV-Profiling. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)