Growth of epitaxial aluminum nitride (AlN) and crystalline superlattices of aluminum nitride/zirconium nitride (AlN/ZrN) on Si(111) by ultrahigh-vacuum dc magnetron reactive sputtering has been studied. Detailed structural characterizations were carried out with techniques of x-ray diffraction, transmission electron microscopy, and reflection high energy electron diffraction. Results on epitaxial orientation, defect configuration, and growth mode are discussed.