Diode-Like Field Emission Devices Fabricated by Standard 0.35-μm CMOS MEMS Process

This research presents a new method for manufacturing field emission devices (FEDs) using a standard 0.35- $\mu $ m CMOS MEMS fabrication process, allowing the devices to function in normal air conditions. To enable nanoscale electrode gaps and atmospheric pressure operation, the FED’s layout is strategically modified to function as a diode, deliberately bypassing certain design rules for low-voltage capability. The SEM images suggest that the actual gap distance separating the electrodes is typically smaller than the initially intended dimensions. Measurements reveal an inverse relationship between the diode-like FEDs’ threshold voltages and the designed electrode spacing. These diode-like FEDs exhibit gentle rectification behavior, especially those with lower threshold voltages. This approach drastically simplifies FED fabrication, demonstrating the feasibility of integrating FEDs with CMOS technology. While the current 0.35- $\mu $ m CMOS MEMS process employs aluminum metal stacks, this material choice may compromise reliability, especially when exposed to high-frequency alternating voltages.