A method of fabricating a MEMS structure includes providing a substrate comprising a logic element region and a MEMS region. Next, a logic element is formed within the logic element region. A nitrogen-containing material layer is formed to cover the logic element region and the MEMS region conformally. Then, part of the nitrogen-containing material layer within the MEMS region is removed to form at least one shrinking region. Subsequently, a dielectric layer is formed to cover the logic element region and MEMS region, and the dielectric layer fills in the shrinking region. After that, the dielectric layer is etched to form at least one releasing hole, wherein the shrinking region surrounds the releasing hole. Finally, the substrate is etched to form a chamber.