Exploring Measurement Techniques and Challenges in Silicon Based Field Emission Arrays

Silicon field emission arrays (FEAs) fabricated by laser-micromachining offer high-current electron sources for vacuum nanoelectronics applications. Compared to previous work using scintillator screens inside vacuum chambers to study emission Patterns (4×4 arrays, max 15 μA at 350 V [9]), our design achieves higher currents from denser 21×21 arrays. Electrical testing demonstrated good performance, with emissions of 300-500 μA from samples without a grid and up to 1 mA from those with grid configurations (both with 21×21 tips on an 8.5×8.5 mm² chip, same emission area as previous designs). Unlike earlier integral current measurements or scintillator imaging that could not quantify individual tip contributions, our CMOS sensor method enables spatially resolved current mapping. Spatially resolved emission current measurements showed that this total current comes from only ≈ 20 % of the available tips, indicating significant potential for 2-3 times total current increase through better tip activation and opportunities to improve emission uniformity for homogeneous beam applications.