Day: April 9, 2012

Characterization of Trap States in HfO2 with Atomic Scale Spatial Resolution Using Single Electron Tunneling Force Spectroscopy

Friday, April 13, 2012
3:00 pm – 4:00 pm
Room 610, M&M Building
Dustin Winslow
University of Utah
The rapid advancement of technology has led to increasingly faster and smaller solid state devices. One reason for this rapid development is the dedicated effort to characterize the defects in the dielectric materials used in solid state electronics. While many techniques have been developed over the years to characterize trap states in dielectric materials no technique has allowed for characterization of localized electron and hole trap states, in completely nonconducting films, with atomic scale spatial resolution. This talk will focus on the force detected tunneling techniques developed in the Williams lab at the University of Utah over the last decade, with an emphasis on the recently developed single electron tunneling force spectroscopy (SETFS) technique. The apparent density of localized trap states in HfO2 measured using SETFS will be compared to experimental results and theoretically predicted values found in the literature. The convoluted nature of the apparent energy and physical depth information of the trap states will be discussed, and the methodology to separate this information will be explained. Finally, evidence of mobile charge in HfO2 will be presented and a possible mechanism proposed to explain the irreversible nature of the surface charging.