Silicon Nanowires embedded pressure sensor with annularly grooved diaphragm for sensitivity improvement

A NEMS piezoresistive pressure sensor with annular grooves on the circular diaphragm is presented here. Silicon Nanowires (SiNWs) are embedded as sensing elements at the edge of the diaphragm. This new diaphragm structure improves the device sensitivity by 2.5 times under a low pressure range of 0~120 mmHg with respect to our previously reported flat diaphragm pressure sensor. With the advantage of superior piezoresistive effect of SiNWs, this sensitivity improvement is even remarkable in contrast to other recently reported piezoresistive pressure sensing devices. Additionally, by leveraging the miniaturized sensing diaphragm (radius of 100 μm), the sensor can be potentially used as implantable device for low pressure sensing applications.