Analysis of MEMS diaphragm of piezoresistive intracranial pressure sensor

Abstract

In the present paper, the design and simulation of square diaphragm, MEMS piezoresistive pressure sensor for intracranial application has been presented. The pressure sensor design presented in this paper consists of a carbon nanotube (CNT) suspended on a square and slotted shaped diaphragm as piezoresistor. The slot was added into the design of the square diaphragm to reduce the residual stress and stiffness of diaphragm. This kind of pressure magnifying scheme is utilized so that placement of the piezoresistor will be on the most sensitive part of the diaphragm, which is at the maximum stress locations on the diaphragm. The static analysis of the system is performed using FEM model of COMSOL Multiphysics. Two sensor designs incorporating square and slotted square diaphragm are implemented and compared to realize the pressure-sensitive components. The pressure sensor has been designed to measure pressures in the range of 0 to 10 mmHg that is in the range of intracranial pressure sensors. The change of resistance of piezoresitors placed on the maximum stress area of slotted square diaphragm was found to be linear with respect to the applied pressure.