EPITAXIAL OVERGROWTH OF C-13 DIAMOND FILMS ON DIAMOND SUBSTRATES PREDAMAGED BY ION-IMPLANTATION

Homoepitaxial chemical vapor deposited (CVD) C-13 diamond films were g rown on [100] diamond substrates predamaged by implantation with 620 k eV Xe ions. The structural quality of the overgrown films was analyzed by plain-view and cross-sectional micro-Raman spectroscopy. Implantat ion doses below 2X10(14) cm(-2), for which no damage detectable by Ram an spectroscopy was observed in the substrate, had no effect on the qu ality of the overgrown films. For doses around 4X10(14) cm(-2), a pron ounced predamage of the diamond substrate was found which had a strong degrading effect on the quality of the overgrown layer resulting in a drastic increase of the width of the optic zone-center phonon and in the appearance of Raman scattering from sp(2)-bonded carbon. Higher im plantation doses up to 1X10(15) cm(-2) resulted in a complete etch rem oval of the predamaged graphitic surface layer during the initial phas e of CVD growth, which thus had no effect on the quality of the film p roduced by the subsequent overgrowth. (C) 1997 American Institute of P hysics.