Design of diaphragm structure for piezoresistive pressure sensor using topology optimization

Micro piezoresistive pressure sensor has become one of the most widely used microelectromechanical systems devices due to its high sensitivity, low cost and simple fabrication. For developing piezoresistive pressure sensor, one of the most important considerations is the configuration (structure) of the diaphragm. Although various types of diaphragm structure have been proposed, they are often designed intuitively, and thus to a large extent they depend on the designers' intuition and experience. This paper presents a systematic approach for designing diaphragm structures for piezoresistive pressure sensor by using topology optimization. The design problem is treated as a three dimensional topology optimization problem with design dependent loads in which the dependence is regarded due to transmissible loads. The objective is to minimize the mean compliance to achieve high linearity. Several geometrical constraints are developed to achieve high sensitivity. The design problem is solved by using the popular SIMP (Solid Isotropic Material With Penalization) method. A number of design examples are used to demonstrate the ability of the procedure to generate nonintuitive diaphragm structures. Solutions obtained from this procedure are compared with diaphragms with other configurations reported in the literature.