Photoemission Characterization of Interface Dipoles and Electronic Defect States for Gate Dielectrics

Abstract

We have demonstrated how inner potential changes due to electrical dipole moments at interfaces in dielectric stacks are directly evaluated by measuring the cut-off energy of secondary photoelectrons in the lower kinetic energy side, in which near-surface band bending is taken into account from an energy calibration of core-level photoelectrons. We have also showed how useful photoelectron electron yield spectroscopy (PYS) is to quantify the energy distribution of filled gap states and defect states even in widegap materials and their heterostructures such as a SiO2/GaN stack.