Role of the tip induced local anodic oxidation in the conductive atomic force microscopy of mixed phase silicon thin films

Abstract

AbstractWe show that local currents observed by the Conductive Atomic Force Microscopy (C‐AFM) of silicon thin films measured in ambient atmosphere are generally limited by surface oxide, either native or created by the measurement itself in a process of Local Anodic Oxidation (LAO), as evidenced by observed topographic changes of Si surface. The tip‐induced LAO changes the character of the local current maps in repeated scans or even in the first scan of a pristine surface. In particular, the oxidation of the neighboring scan lines leads to the appearance of grain edges as conductive rings. Finally, we have used brief HF acid etch to strip the oxide in order to restore the contrast in the C‐AFM maps of aged samples and we compare the observed local current levels to those observed in ultra‐high vacuum C‐AFM on in‐situ deposited samples (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)