Characterization of Silicon Nanowire Embedded in a MEMS Diaphragm Structure Within Large Compressive Strain Range

The characteristics of piezoresistive silicon nanowires (SiNWs) under compressive strain as large as 1.7% are reported. The SiNW is embedded in a multilayered diaphragm structure consisting of silicon nitride and silicon oxide. After leveraging the high fracture stress and intrinsic tensile stress of silicon nitride layer to produce a flat diaphragm, we can create large compressive strain to the SiNW without damaging the diaphragm. The relationship between SiNW resistance change and applied strain is measured and investigated with 2-μm and 5-μm SiNWs for both scientific and practical points of view. This approach demonstrates the validity to reveal the SiNW properties under large strain, and the exploration provides good reference for future SiNW-based MEMS sensor design.