The Surface Impurities Depth-Profiling on the Diamond

The surface impurities on the diamond were determined and analyzed by the secondary ion mass spectroscopy (SIMS). In order to obtain the depth-profiling of the surface impurities, the ion erosion method was used. The total erosion time was 6 400 s by Ar+ at 15 keV, and N, Na, Mg and Si were chosen as the impurities to be observed. The results indicate that the concentration maximums of the various impurities are situated in a thin layer near the most outward surface and its erosion time correspond to less than 6.5 min; the concentrations for a given impurity, at the most outward surfaces of two different samples, may differ enormously; if the erosion time exceed 30 min, however, this concentration difference in different samples is not large. Also variations in impurities concentrations are not obvious as the erosion time (i. e. as the depth) increases, in the same sample.