PROBING CONDUCTING PARTICLES BURIED IN A NI-X(SIO2)(1-X) COMPOSITE BYCONDUCTING ATOMIC-FORCE MICROSCOPY

In this article, we present an experimental study on probing conductin g particles buried in a Ni-x(SiO2)(1-x) composite with x around the pe rcolation threshold x(c) by conducting atomic force microscopy (C-AFM) . The buried conducting particles were ''observed'' via the electric c urrent image of C-AFM at constant bias. The current from buried conduc ting particles originates from held assisted tunneling through the ins ulating layer. Examples of measuring the thickness of the insulating l ayer will be given. The analysis shows that it is possible to probe th e buried metal particles as deep as several nanometers underneath the surface. By correlating the surface topographic and the current image, the profile of the metal-insulator interface can be measured. General issues on spatial resolution will also be discussed in this article. (C) 1998 American Vacuum Society.