Automated electrochemical CV profiling of LED structures on wafer scale

Abstract

A newly developed equipment is presented to perform (photo-)electrochemical (PEC) CV profiling in semiconductor structures. The equipment is fully automated to handle sample sizes from some mm2 up to 6″ wafers. Fully automated loading of the electrochemical cell, fluid handling system, automatic unloading of the fluid, and drying of the sample at the end of the measurement are incorporated into the setup. Furthermore, together with a wafer stepper it is possible to perform wafer topography measurements. The hardware makes use of a recently, especially for group III-nitrides developed etch procedure named “cyclic oxidation”: featuring high etch rates in the range of 3 μm/h for n- and p-type (Al,In)GaN layers together with mirror-like etched surface morphology. Using this new equipment, LED structures have been characterized by CV profiling. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)