Characterization of thin and ultra-thin SiO2 films and SiO2/Si interfaces with combined conducting and topographic atomic force microscopy

In this work SiO2 films with nominal thickness of 1.3, 2.4 and 5.3 nm are characterised. This includes for the 1.3 nm and 2.4 nm material topographic imaging of the SiO2 surface and the SiO2/Si interface after removing the oxide layer at exactly the same position in addition to electrical characterization and determination of the oxide thickness with ultrahigh spatial resolution. A single equation is derived to determine the electrically active thickness of the oxides from tunnelling current measurements. This equation holds for both, the Direct Tunnelling and Fouler Nordheim Tunnelling regime with one single parameter set. By these means a direct correlation between interface structure, surface structure and high current spots in MOS transistors could be revealed. (C) 2003 Elsevier Ltd. All rights reserved.