Effect of internal mechanical stresses in a multilayer structure on displacement for various designs of microelectromechanical membranes

In the manufacture of microelectromechanical sensors based on multilayer membranes, internal mechanical stresses arise in the structure. A preliminary assessment of the effect of internal mechanical stresses on the initial  displacement of structures of various shapes will allow to choose the most appropriate design solution for various applications. The paper presents the results of numerical modeling of the structures of multilayer membranes of three types: round, square and square with transverse and angular beams. The displacement values for each type of multilayer membranes are obtained in accordance with the influence of internal mechanical stresses in each layer. The  results showed that the effect of internal mechanical stresses in films (SiO₂, Mo, ZnO) of a multilayer structure on square and round membranes is insignificant (values ranged from 2.43·10^–13 to 7.83·10^–13 nm). Internal mechanical  stresses in membrane layers with transverse and angular beams make a significant contribution to the initial displacement of the structure (values ranged from 20 to 570 nm), however, the sensitivity of such structures is  higher than that of rigid structures. The influence of technological conditions of film formation in multilayer membranes on their stress-strain state in ultrasonic sensors is investigated. The values of internal mechanical stresses in  SiO₂ films are obtained.