A metal-oxide-semiconductor field-effect transistor (MOSFET) with integrated passive structures and methods of manufacturing the same is disclosed. The method includes forming a stacked structure in an active region and at least one shallow trench isolation (STI) structure adjacent to the stacked structure. The method further includes forming a semiconductor layer directly in contact with the at least one STI structure and the stacked structure. The method further includes patterning the semiconductor layer and the stacked structure to form an active device in the active region and a passive structure of the semiconductor layer directly on the at least one STI structure.