A semiconductor device and a method for fabricating the semiconductor device using a damascene process are disclosed. The method includes forming an Al2O3 film over a dummy gate disposed over a semiconductor substrate. Next, the dummy gate and a portion of the Al2O3 film are removed to form a groove defined by remains of the Al2O3 film and the semiconductor substrate. Then, a subsequent film is deposited within the groove, and a gate material is formed over the second film to complete the semiconductor device.