Abstract
The fabrication of microfluidic devices with precise droplet generation capabilities is critical for research in cell and biomaterial handling, aerosol drug delivery, and additive manufacturing. Furthermore, there is a need for the scalable production of nozzles which are consistent and uniformly sized. A scalable fabrication technique involving the wet etching of silicon provides this solution. The etching of a silicon nitride coated (around 650 nm thick) silicon wafer (around 500 µm thick) by potassium hydroxide (KOH) is simple compared to more direct fabrication methods, and the crystal structure of silicon induces the formation of natural pyramid shaped nozzles. This study conducted a wet etch at 65oC while ultrasonicating the bath at 80 kHz. The resulting micro-nozzle array had nozzle angles of 54.6o (consistent with literature) and experienced a base width expansion (horizontal etching at the surface) of 3% and 3% after 18 and 20 hours respectively. The etch rate was found to be 26 µm/hr.
Document Type
Final Report
Class Name
Mechanical Engineering and Material Sciences Independent Study
Date of Submission
5-10-2024
Recommended Citation
Patel Masini, Nirvan, "Characterization of a Potassium Hydroxide Wet Etch of Silicon Nitride Masked Silicon Substrates for Pyramidal Micro-nozzle Array Fabrication" (2024). Mechanical Engineering and Materials Science Independent Study. 265.
https://openscholarship.wustl.edu/mems500/265