A method for forming a semiconductor device structure is provided. The method includes forming a semiconductor layer on a semiconductor substrate, forming an interfacial layer on the semiconductor layer, forming a first gate dielectric layer on the interfacial layer, introducing fluorine on the first gate dielectric layer, annealing the first gate dielectric layer, forming a second gate dielectric layer on the first gate dielectric layer, introducing fluorine on the second gate dielectric layer, annealing the second gate dielectric layer, and forming a gate stack structure on the second gate dielectric layer.