A microphone includes a base with a port extending therethrough, and a microelectromechanical system (MEMS) device coupled to the base. The MEMS device includes a diaphragm, a back plate, and a substrate. The substrate forms a back-hole. A capillary structure is disposed in the back-hole of the substrate, the cover, adjacent to the MEMS, or combinations thereof. The capillary structure includes a plurality of capillaries extending through the capillary structure. The capillary structure may have at least one hydrophobic surface and is configured to inhibit contaminants from outside the microphone from reaching the diaphragm via the port. In some embodiments, the capillary structure may protect against EMI.