CNC machining of lithium niobate for rapid prototyping of sensors

CNC machining offers an alternative fabrication route to clean room approaches for the prototyping of sensor designs. Its flexibility and cost effectiveness makes it an ideal option as a fabrication route during the preliminary research phase of a project. However, resonant based sensors predominantly rely on crystalline materials to achieve high quality factors. This work reviews the state-of-the-art device shaping processes of lithium niobate, and looks to assess and optimize CNC machining on the crystalline lithium niobate towards fabrication of resonating diaphragms targeted towards biosensing applications. Initial results indicate that machining produces a smooth vertical sidewall with a surface finish on the cutting face of around 80 nm. Resonator quality factor, assessed by observing the fundamental vibration at atmospheric pressure, is 90. Steps on improving the machining process are discussed.