A fully embedded micromechanical device and a system on chip is manufactured on an SOI-substrate. The micromechanical device comprises a moveable component having a laterally extending upper and lower surface and vertical side surfaces. The upper surface is adjacent to an upper gap which laterally extends over at least a part of the upper surface and results from the removal of a shallow trench insulation material. The lower surface is adjacent to a lower gap which laterally extends over at least a part of the lower surface and results from the removal of the buried silicon oxide layer. The side surfaces of the movable component are adjacent to side gaps which surround at least a part of the vertical side surfaces of the moveable component and result from the removal of a deep trench insulation material.