Design and computational analysis of diaphragm based piezoresistive pressure sensors for integration into undergraduate curriculum

In order to expand undergraduate education in microelectromechanical systems (MEMS), and nanotechnology, a series of sensors were designed with the intent of integrating the design process into the project portion of a micro/nano systems course. The majority of the design work was focused around piezoresistive, diaphragm-based pressure sensors, utilizing multiple diaphragm sizes and geometries. These sensors were chosen for their geometrical simplicity and their ability to be manufactured using available photolithographic techniques. In order to gain a deeper understanding of the stress distribution in these sensors, leading to better design decisions, the Finite Element Analysis (FEA) technique was used. Results from this analysis were validated using analytical models available in the literature. Once this validation was accomplished, multiple iterations of FEA were performed in order to gain further understanding of the stress variation relative to diaphragm specifications. The results of these simulations were used to optimize the placement of the piezoresistors on the diaphragm and to assess the effect of process variation on the performance of the device. This analysis procedure aided in the design of pressure sensors with different sets of diaphragm geometries. The design and analysis procedures were documented and followed by students enrolled in the Nanosystems Engineering course to design and analyze the sensor type of their choice.