A new AFM-based tool for testing dielectric quality and reliability on a nanometer scale

Conducting AFM (C-AFM) makes it possible to measure local tunneling currents through thin dielectrics with a lateral resolution of a few nanometers. Thereby root causes for oxide fails like thickness inhomogeneity, electrically weak spots or local degradation can be detected. The method yields local currents down to the fA range, thickness determination in the range from 1 nm to 80 nm with an absolute accuracy down to 3A, and high resolution thickness maps. We show examples of gate oxide edge thinning, EEPROM data retention fails and low QBD MOS oxides. © 1999 Elsevier Science Ltd. All rights reserved.