IMPURITIES OF LIGHT-ELEMENTS IN CVD DIAMOND

CVD diamond samples were investigated for their content of light elements and their influence on the physical properties by high resolution elastic recoil detection (ERD) analysis. ERD allows quantitative measurements of depth profiles for all light elements with a depth resolution better than 1 nm (near the surface) using Ni-58 Or I-127 ions with a specific energy of about 1 MeV per nucleus and a high resolution magnetic spectrograph. The measurements were focused on the content of hydrogen in (100)oriented CVD diamond 90 mu m thick grown on (100) silicon. The hydrogen content varied from 0.07 at.% in the bulk to several atomic per cent for fine crystalline diamond near the interface to its silicon substrate. The hydrogen coverage of (100)-oriented diamond could also be determined to be near the value which is expected if the (100) surface has a (2 x 1) reconstruction. In addition to hydrogen, other light elements were simultaneously measured. Silicon and oxygen impurities were also analysed in order to get information about their physical relevance. A correlation between the Si content and the luminescence of silicon centres was attempted.