Abstract
The tunneling current versus voltage characteristic of the Sc2O3/La2O3/SiOx high-kappa gate stack is examined using scanning tunneling microscopy in ultrahigh vacuum. Different measurement bias polarities allow information on the location (i.e., in the high-kappa or interfacial SiOx layer) of the electronic traps to be extracted. Two types of localized leakage sites may be distinguished. Lowering of the electron barrier height and trap-assisted tunneling are proposed as the two leakage mechanisms. (c) 2008 American Institute of Physics.