Residual Stress of Graphene-Based MEMS ICP Piezoresistive Pressure Sensors

Thin diaphragm play an important role in highly sensitive MEMS piezoresistive pressure sensor for intracranial pressure measurement. The thinness of graphene was utilized in this pressure sensor to maximize the sensitivity of the ICP pressure sensor. However a very thin diaphragm can cause a pressure nonlinearity performance problem due to the residual stresses. This present paper study the effect of residual stress due to different number of graphene layers on MEMS intracranial (ICP) piezoresistive pressure sensor. COMSOL simulation was used to determine the pre-stressed deformed square diaphragm hence the value for residual stress of single layer and multilayer graphene can be calculated. It was found that the application of multilayer graphene can reduce the effect of residual stress on graphene based MEMS ICP piezoresistive pressure sensor. Residual stress of 1.94 x 10(7) Mpa was reduced to 9.72 x 10(3) Mpa by utilizing 20 layers of graphene. This study has suggested a simplified method to produced highly sensitive pressure sensor with reduced pressure non linearity problem by using multilayered graphene diaphragm instead of complicated single layer application method.