process next etching process and or chemical mechanical polishing cmp process could be conducted to remove part of the dielectric layer 30 for forming a shallow trench isolation sti transistor elements including gate structure and source drain regions could also be formed thereafter depending on the demand of product and the details of which are not explained herein for the sake of brevity it should be noted that the aforementioned annealing process not only drives dopants from the doped layer 24 into the bottom portion 20 of fin shaped structures 14 and or substrate 12 it also solidifies the originally flowable and viscous dielectric layer 30 formed through fcvd process into a much more solid and concrete structure removes part of impurities such as nitrogen and hydrogen from the dielectric layer 30 and repairs layer defect thereby increasing isolation effectiveness it should be noted that instead of performing annealing process to drive dopants from the doped layer 24 into bottom portion 20 and or substrate 12 after depositing the dielectric layer 30 it would also be desirable to perform annealing process before the formation of dielectric layer 30 such as after removing liner 26 and doped layer 24 not protected by the dielectric layer 28 and before removing the dielectric.