Visualizing the Electrostatic Barrier of a Material Interface to Nanoscale Dimensions: Defects, Silicides, and Dielectrics

Electrostatic barriers at material interfaces are the foundation of current and futuristic electronic and optoelectronic devices. Direct visualizing of the electrostatic barrier of an interface with nanoscale resolution can be accomplished utilizing ballistic electron emission microscopy (BEEM), an STM-based technique [1]. Tens of thousands of BEEM spectra are acquired on a regularly spaced grid and then fit to extract the Schottky barrier height. Physical and chemical insight is provided by computational modeling, which simulates the distributions of barrier heights and includes effects from the interface and transport of the hot electrons in the metal. This presentation will give an overview of the technique and its ultimate spatial and energetic resolution. Measurements of defects, incomplete silicide formation, the presence of multiple metal species at the interface, monolayer thick dielectric layers, and the influence of ionized impurity scattering in the semiconductor will also be presented.
[1] Westly Nolting, Chris Durcan, Steven Gassner, Joshua Goldberg, Robert Balsano, Vincent P. LaBella, Journal of Applied Physics, 123 245302 (2018).