Investigating PMMA as a potential insulator material for metal-insulator-metal diode

The metal-insulator-metal (MIM) diodes are considered very promising for high frequency applications because of its tunnelling-based ultrafast charge transport mechanism. A wide variety of materials are being explored in quest of developing these thin film devices. Recently, organic insulator-based MIM diodes have attracted significant attention to the researchers due to its several advantages and have become a promising alternative of conventional inorganic insulators. In the present work the feasibility of an organic polymer polymethyl methacrylate (PMMA) is investigated for insulating material of MIM junction. It is a transparent resin which is able to produce uniform and thin insulating layer with low defect density. In this work, an Al/PMMA/Cr structure is fabricated by optimising different process parameters in order to develop high performance, reproducible organic MIM diodes. The as fabricated device exhibited fairly asymmetric and nonlinear current-voltage characteristics, which reveals the viability of PMMA as candidate material for insulator layer in MIM diodes.