The problems of increasing the reliability of microelectromechanical systems are considered on the example of an automobile voltage regulator. A model of the process is proposed and a study of the effect of temperature on the formation of stress fields in semiconductor structures of active elements of the controller is carried out. The studies assumed of a possible reason for the change in the parameters of the regulator due to the appearance of defects in the crystal structure of the semiconductor material in the structures of integrated voltage regulators. For the study, a mathematical model was proposed that describes the behavior of a semiconductor element of a real car voltage regulator. It was found that the distribution of stresses in the structures is uneven and the maximum value of stresses reaches the edges., An increase in temperature gradients in the structures of regulators leads to the formation of dislocations that change the electrical characteristics of devices. As a result of modeling, it has been established that thermoelastic stresses arising in the process of manufacturing and functioning of semiconductor structures of a regulator in regulators of this type can cause a change in the structure of a semiconductor device due to relaxation of elastic stresses at dislocations. in cars. Measures are proposed, including thermostating of the sensitive elements of microelectromechanical structures, which will increase their service life.