Tungsten-SiO₂-Based Planar Field Emission Microtriodes with Different Electrode Topologies

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Field emission microtriodes are crucial for various electronic applications.
• Tungsten (W) and silicon dioxide (SiO2) are key materials in microelectronics.
• Optimizing microtriode performance requires understanding material properties and fabrication methods.

Purpose of the Study:

• To investigate and compare the electrical properties and layer quality of field emission microtriodes.
• To analyze microtriodes fabricated using photolithography (PL) and focused ion beam (FIB) techniques.
• To correlate material characteristics with field emission performance.

Main Methods:

• Fabrication of multi-tip (PL) and single-tip (FIB) microtriodes with planar electrode geometry.
• Atomic force microscopy (AFM) for surface roughness analysis.
• Photoelectron emission (PE) spectroscopy for work function determination.
• X-ray photoelectron spectroscopy (XPS) for elemental composition and purity analysis.

Main Results:

• Tungsten layer surface roughness was measured at Ra = 3.8 ± 0.5 nm.
• Work functions were determined for Si (4.71 eV), SiO2 (4.85 eV), and W (4.67 eV).
• XPS confirmed W layer homogeneity and absence of impurities.
• FIB microtriodes had a lower turn-on voltage (50 V) than PL microtriodes (110 V).
• Both devices achieved a field emission current of 0.4 nA.

Conclusions:

• Focused ion beam (FIB) fabrication yields significantly improved field emission efficiency compared to photolithography (PL).
• The enhanced performance of FIB microtriodes is attributed to a higher local electric field at the cathode.
• The study highlights the importance of fabrication methods in optimizing microtriode performance for electronic applications.