Metal–Insulator–Insulator–Metal (MIIM) Ag/SnO$_2$/Al$_2$O$_3$/Ag Diodes Fabricated by Ultraprecise Dispensing and Atomic Layer Deposition

Currently, high-frequency, ultra-fast, and tunneling diodes are mainly fabricated using traditional lithography and evaporation techniques, typically limited to wafer sizes. This work introduces a new method for fabricating metal–insulator–insulator–metal (MIIM) diodes using ultra-precise dispensing (UPD) printing techniques, providing a practical alternative to traditional lithography. Enabling highly precise material deposition, minimizing waste and boosting manufacturing efficiency. Both bottom and top electrodes of the MIIM diode are silver(Ag) and fabricated via UPD, while atomic layer deposition (ALD) is employed to deposit the insulating layers. 1 nm of tin oxide(SnO2) and 1 nm of aluminum oxide(Al$_2$O$_3$) sandwiched between the electrodes: The Ag/SnO$_2$/Al$_2$O$_3$/Ag MIIM diode has a contact area of ca. 5.4 µm × 4.0 µm determined by FIB-SEM. A quantum simulator based on the Wentzel-Kramers-Brillouin (WKB) method is used to analyze the diode's performance and shows agreement with measurement results. The electrical characterization of the fabricated MIIM device exhibits a tunneling current in the nano- to microampere range, a zero-bias responsivity of −1.31 A/W, and dynamic resistance of 39.56 kΩ. ... mehrCombining ultra-precise printing with innovative insulators provides a promising pathway to large-scale, low-cost production of high-performance MIM diodes for energy harvesting, high-frequency rectification, and flexible applications electronics.