Self-Assembled Metal–Insulator–Metal Tunnel Junctions

Abstract

Metal–insulator–metal (MIM) tunnel junctions have various applications in microelectronics. As a core building block within this space, these simple structures are fabricated using conventional patterning, deposition, and etching techniques. As such, MIM devices are subject to the inherent limitations and undesirable byproducts of these techniques. Herein, an alternative approach to MIM tunnel junction fabrication is presented, in which classical patterning is used in conjunction with bottom-up, self-assembly to form these structures. Area-selective deposition is utilized to grow encroaching electrodes that terminate at their meeting point to make junctions. The resulting resistances of these junctions are found to be independent of their initial spacing, an indication of self-limited growth. Temperature dependence of these resistances and the behavior of these devices upon annealing indicate electronic tunneling as the dominant transport mechanism. Analysis of these properties is used to estimate barrier thicknesses and conclude that steric effects are the likely reason for self-limitation.