Abstract Growth of CN films on Si (111) is realized by ionized cluster beam (ICB) deposition. X-ray diffraction (XRD) shows the occurence of β-C3N4 crystal structure in the films. X-ray photoelectron spectra (XPS) shows 20% N incorporated into the films and two peaks are observed in C1s and N1s, core level spectra respectively. Single bonded CN and triple bonded CN were identifies by infrared absorption spectra. Reflection high-energy electron diffraction (RHEED) demonstracted the coexistence of amorphous and crystalline CN compounds. The Knoop hardness of CN films reaches 6200 kgf/mm2.