Characteristics of NEMS piezoresistive silicon nanowires pressure sensors with various diaphragm layers

Abstract

Optimized diaphragm structures comprising silicon nitride (SiNx) film integrated with piezoresistive silicon nanowires (SiNW) are characterized for nanoelectromechanical system (NEMS) pressure sensors. Several improvements are done in comparison with our previously reported device [1]. Firstly, p-type SiNWs of 1 μm with 1E14 implantation instead of 10 μm 1E13 implantation are adopted to gain more uniform stress and show better linearity. Secondly, by using SiO 2+SiNx bi-layer film instead of pure SiO 2 film, the membrane is not only flat, but also toughened to be able to withstand pressure up to 40 atm. Finally, the real test shows that the sensitivity of pressure sensor is doubled by thinning down the SiNx film to half thickness. © 2011 Published by Elsevier Ltd.