Optimization of NEMS pressure sensors with a multilayered diaphragm using silicon nanowires as piezoresistive sensing elements

A pressure sensor with a 200 µm diaphragm using silicon nanowires (SiNWs) as a piezoresistive sensing element is developed and optimized. The SiNWs are embedded in a multilayered diaphragm structure comprising silicon nitride (SiNx) and silicon oxide (SiO2). Optimizations were performed on both SiNWs and the diaphragm structure. The diaphragm with a 1.2 µm SiNx layer is considered to be an optimized design in terms of small initial central deflection (0.1 µm), relatively high sensitivity (0.6% psi−1) and good linearity within our measurement range.