Abstract
A semiconductor device structure is provided. The semiconductor device structure includes a semiconductor substrate. The semiconductor device structure includes a first gate stack which is positioned and set on the semiconductor substrate. The semiconductor device structure includes a first doped structure and a second doped structure which are positioned and set on two opposite sides of the first gate stack, and embedded in the semiconductor substrate. The semiconductor device structure includes a second gate stack which is positioned and set to be adjacent to the second doped structure and on the semiconductor substrate. The semiconductor device structure includes a third gate stack which is positioned and set on the semiconductor substrate. The semiconductor device structure includes an isolation structure embedded between the second gate stack and the third gate stack and on the semiconductor substrate. The isolation structure is wider and thinner than the second doped structure, and the isolation structure is made of an epitaxial material.