Cathodoluminescence characteristics of polycrystalline diamond films grown by cyclic deposition method

Abstract

Polycrystalline diamond films were deposited using a cyclic deposition method where the H2 plasma for etching (tE) and the CH4+H2 plasma for growing (tG) are alternately modulated with various modulation ratios (tE/tG). From the measurement of full width at half maximum and ID/IG intensity ratio obtained from the Raman spectra, it was found that diamond defects and non-diamond carbon phases were reduced a little by adopting the cyclic deposition method. From the cathodoluminescence (CL) characteristics measured for deposited films, the nitrogen-related band (centered at approximately 590 nm) as well as the so-called band-A (centered at approximately 430 nm) were observed. As the cyclic ratio tE/tG increased, the relative intensity ratio of band-A to nitrogen-related band (IA/IN) was found to monotonically decrease. In addition, analysis of X-ray diffraction spectra and scanning electron microscope morphologies showed that CL characteristics of deposited diamond films were closely related to their crystal orientations and morphologies.