Mfg. detector of dynamic parameters, e.g. accelerometer

摘要

The dynamic state parameter is detected from the separation of a movable part. On the silicon layer contg. substrate main surface is formed an acceleration detecting element, as well as a control circuit for delivering a signal in response to the acceleration, which has a MOSFET for preparation of a signal from the acceleration detector. The polycrystalline silicon layer is formed, while the substrate is kept on a first temp. giving a tensile stress in the silicon layer. In a third step the substrate is heat treated at a second temp., reducing the tensile stress to zero, but preventing diffusion of doped impurities from the MOSFET into the substrate.