Разработка чувствительного элемента микромеханического акселерометра

Abstract

Micromechanical accelerometers have wide range of applications in industry and robotechnics due to the main advantages such like low power consumption, small dimensions and weight, low cost in serial production. Therefore, micromechanical accelerometers research and development received priority. In this work, finite element analysis software was used for modeling the sensitive element, for this method allows providing static and modal analysis. The results of preliminary calculations of the scale factor of the accelerometer that can be assembled based on the developed sensor and sigma-delta transducer, are provided. The article describes the tech-nological process of manufacturing sensitive elements of micromechanical accelerometers. In this case, anisotropic liquid chemical etching of silicon was used, which makes it possible to obtain different profiles of the corresponding crystallographic planes. The results of a study of the influence of technological errors on the geometric dimensions of sensitive elements are provided: the dependence of the value of the lateral undercut of silicon on the accuracy of the angular alignment of the mask with the crystallographic axis of the plate (100) was revealed. The design of the sensitive element of the micromechanical accelerometer has been developed. The performed simulations have proved out the performance of the structure, the calculations have shown the change in the scale factor in the temperature range from –60 to +125 °C, the value of the nominal capacity and capacity with a change in linear acceleration in the range of ± 60 g. In the manufacture of a sensitive element on the basis of the studies carried out, it is possible to ob-tain a lateral undercut of no more than 5 microns at a depth of anisotropic liquid chemical etching of 250 microns for KDB-0,01 plates with an orientation tolerance of ± 30 arc minutes or with a misorientation of the same magnitude allowed during exposure.