Cathodoluminescence characteristics of polycrystalline diamond films grown by cyclic deposition method

Abstract

Polycrystalline diamond films were deposited using a cyclic deposition method where the H-2 plasma for etching (t(E)) and the CH4+H-2 plasma for growing (t(G)) are alternately modulated with various modulation ratios (t(E)/t(G)). From the measurement of full width at half maximum and I-D/I-G 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 t(E)/t(G) increased, the relative intensity ratio of band-A to nitrogen-related band (I-A/I-N) 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. (C) 2002 Elsevier Science B.V. All rights reserved.