Crystalline boron carbide (BC) films were synthesized on n-type Si(111) surface by employing pulse DC plasma chemical vapor deposition (CVD) technique. In the present study, ortho-carborane was used as precursor in order to obtain p-type BC films so that a p-n junction diode is formed. X-ray diffraction of BC films showed well defined crystallized reflections with presence of several boron carbide phases. The measured direct band-gap and resistivity of these films were ~3.2 eV and 75000-100000 Ohm.cm respectively. I-V characteristics of such films confirmed about the formation of p-n junction diode between BC:Si interface with a leakage current of 50 nA at -40 V.