Transport localization in heterogeneous Schottky barriers of quantum-defined metal filmsF. Giannazzo1, F. Roccaforte1, V. Raineri1 and S. F. Liotta2
1 CNR-IMM - Stradale Primosole 50, 95121 Catania, Italy
2 STMicroelectronics - Stradale Primosole 50, 95121 Catania, Italy
received 30 January 2006; accepted in final form 10 March 2006
published online 5 April 2006
The nanometric localization of current transport in heterogeneous Schottky barriers was obtained by the combination of the electric field localization at the apex of a biased conductive atomic force microscopy (c-AFM) tip and of the metal films high-resistivity properties. An abrupt increase of the resistivity, modeled by a quantum-mechanical approach, was measured in Au thin films with a thickness below . For Au ultrathin film resistivity, exceeding by two orders of magnitude the bulk value, the nanometric localization of the current transport occurs. This physical effect represents the basic principle of a microscopy approch for two-dimensional Schottky barrier height mapping, which is alternative to conventional ballistic electron emission microscopy (BEEM). A spatial resolution in the order of the tip diameter (10-) is demonstrated by considering the realistic description of the system (physical and geometrical). Schottky barrier inhomogeneities in a Au/4H-SiC system were imaged with an energy resolution better than .
73.30.+y - Surface double layers, Schottky barriers, and work functions.
73.50.-h - Electronic transport phenomena in thin films.
07.79.Lh - Atomic force microscopes.
© EDP Sciences 2006