On the data interpretation of the C-AFM measurements in the characterization of thin insulating layers

The interpretation of the conductive atomic force microscopy (C-AFM) results is discussed in the framework of the characterization of the high-k layers as gate oxide. Because the high-k layer is deposited on an interfacial layer, at high gate voltage, the C-AFM current maps do not reflect the high-k properties but rather the interface. Moreover, in the point contact mode, the surface of the equivalent capacitor as well as the voltage and current ranges used with the C-AFM are different from the one used in common IV. The interpretation of macroscopic measurements can therefore not be transposed to the C-AFM results. More specifically, the shift towards lower voltage of the backward curve is ascribed to the creation of a conducting path at high voltage. (c) 2004 Elsevier Ltd. All rights reserved.