Rapid, General-Purpose Patterning of Silicon Nitride Thin Films Under Ambient Conditions for Applications Including Fluid Channel and SERS Substrate Formation

Silicon nitride thin films are useful as etch-stop masks in micro- and nanofabrication. As structural elements, they are prevalent in applications as diverse as single-molecule sensing, transmission electron microscopy, ultrafast spectroscopy, superfluidity studies, and high flux liquid filtering. A hand-held “flameless” Tesla-coil lighter was used to create vias through 200 nm silicon nitride (SiNx) films coating silicon wafers. The processing allowed spatially directed KOH etching of the underlying Si. Patterning could be achieved with a hard mask or rastering of the spatially confined discharge, offering—with low barriers to rapid use—particular capabilities that might otherwise be out of reach to researchers without access to conventional, instrumentation-intensive micro- and nanofabrication workflows. General patterning capabilities were demonstrated, followed by the formation of a trench suitable for microfluidic applications. Finally, a discharge-treated thin film surface was sputter coated with gold to create a surface enhanced Raman spectroscopy (SERS) substrate that was then used to detect a test analyte at ppm concentration.