IMPURITIES OF LIGHT-ELEMENTS IN CVD DIAMOND

CVD diamond samples were investigated for their content of light eleme nts and their influence on the physical properties by high resolution elastic recoil detection (ERD) analysis. ERD allows quantitative measu rements of depth profiles for all light elements with a depth resoluti on 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 mag netic spectrograph. The measurements were focused on the content of hy drogen in (100)oriented CVD diamond 90 mu m thick grown on (100) silic on. 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 co uld 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, ot her light elements were simultaneously measured. Silicon and oxygen im purities were also analysed in order to get information about their ph ysical relevance. A correlation between the Si content and the lumines cence of silicon centres was attempted.