Resonant transmission through metallic films is observed when a periodic array of holes is drilled. This phenomenon has been attributed to surface plasmon polaritons. We study a similar system made of an array of slits in a SiC film supporting surface phonon polaritons. We find a resonant transmission in the infrared. The role of surface waves is analyzed. We find that surface waves are excited at resonance but are not a necessary condition to obtain a resonant transmission.