Point-Contact Metal-Insulator-Metal Architecture: A Facile Approach for Material Screening Studies and Beyond

Historically, the point-contact metal-insulator-metal (MIM) architecture constituted the first approach for making MIM diodes for high-frequency rectification applications. Point-contact MIM rectifiers have been shown to operate at frequencies as high as 150 THz. In the last 3 decades, point-contact architectures have given way to more stable planar MIM architectures that are lithographically patterned to yield micro- and nanoscale device areas. But point-contact MIM architectures are still highly useful, for example, in facilitating high-throughput material screening studies. Such screening studies are of critical importance for developing material design rules to help identify optimal MIM materials for various rectification applications. In this chapter, modified approaches to the point-contact MIM architecture are presented. These architectures are employed to study the influence of material properties on rectification performance. This enables the correlation of performance to the work function values of the two metals, the electron affinity of the insulator and the thermodynamic stability of the metal/insulator interface. Material selection criteria are proposed based on these results. From these criteria a two-dimensional MIM material space map is constructed that can help identify and visualize application-specific champion MIM devices based on their material properties such as work function and electron affinity.