A heteroepitaxial semiconductor device includes a bulk semiconductor substrate, a seed layer including a first semiconductor material, the seed layer being arranged at a first side of the bulk semiconductor substrate and including a first side facing the bulk semiconductor substrate, an opposing second side and lateral sides connecting the first and second sides, a separation layer arranged between the bulk semiconductor substrate and the seed layer, a heteroepitaxial structure grown on the second side of the seed layer and including a second semiconductor material, different from the first semiconductor material, and a dielectric material layer arranged on the seed layer and at least partially encapsulating the heteroepitaxial structure, wherein the dielectric material layer also covers the lateral sides of the seed layer.