A semiconductor device structure is provided. The semiconductor device structure includes a substrate, a first fin structure over the substrate, and a FeFET device over a first region of the substrate. The FeFET includes a first gate stack across the first fin structure. The semiconductor device structure also includes first gate spacer layers alongside the first gate stack, and a ferroelectric layer over the first gate stack. At least a portion of the ferroelectric layer is located between upper portions of the first gate spacer layers and is adjacent to the first gate stack.