Design and simulation of high sensitive capacitive pressure sensor with slotted diaphragm

Abstract

This paper presents a high sensitive MEMS capacitive pressure sensor for biomedical applications. Two sensor designs incorporating clamped and slotted 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 60 mmhg that is in the range of intraocular pressure sensors. Intraocular pressure sensors are important in detection and treatment of an incurable disease called glaucoma. The capacitive pressure sensor is formed using p++ silicon diaphragm as a biocompatible material. The novelty of this method relies on p++si diaphragm includes some slots to reduce the effect of residual stress and stiffness of diaphragm. The slotted diaphragm makes capacitive pressure sensor more sensitive. That is more suitable for measuring intraocular pressure sensor. The results yield a sensitivity of 1.811×10-5 1/Pa for the clamped and 5.96×10-5 1/Pa for the slotted pressure sensor with a 0.55 × 0.55 mm2 diaphragm. Furthermore, the pull-in voltage for the clamped pressure sensor is 51v, while the pull-in voltage of the slotted one is 38v.