Epitaxial ZnO films were grown on c-plane SiC-6H substrates using metal-organic chemical vapor deposition. X-ray diffraction coupled theta-2 theta and phi-scans show that the n-type ZnO films have c-axis orientation and in-plane registry with the n-type 6H-SiC substrates. This isotype ZnO/SiC heterojunction shows rectifying characteristics. Electrical measurements exhibit that the reverse current is in the picoampere (10(-12)-10(-10) A) range under the reverse bias of less than 5 V, the on-off current ratio is similar to 10(7), and the ideality factor is similar to 1.23. The surface acoustic wave characteristics in the structure consisting of a piezoelectric ZnO and a semi-insulating SiC-6H substrate were also studied. The structure shows promise for high frequency and low loss rf applications.