Non-destructive characterization of ion-implanted diamond

a position-sensitive micro-spectrophotometer with slightly focused light in transmission mode has been employed to characterize the optical inhomogene ity of the original synthetic diamond crystal (100) surface and a modified carbon layer and its defects induced by low-energy H-2(+) implantation at 1 00 K and room temperature. The distribution of strong absorption relative t o different positions, which starts at around 470 nm down to 280 nm in the VIS-UV regions, reflects a distinctive difference of nitrogen concentration and intrinsic defects in different growth sectors. The typical morphology of the intrinsic or ion-induced defects is showed in a two-dimensional topo graphy adjusted at the near absorption edge (lambda = 430 nm). The relative optical density (OD) and band gap (E-r,E-opt) are deduced via the use of t he normalized transmittance and are used to interpret the energetic ion-ind uced defect and its evolution depending on the implanted dose and annealing temperature. It is found that the gradual change from pale to deep reddish brown color in both the reflection and refraction orientations is associat ed with the dosage levels injected into top submicrometer layer, but is ind ependent of the implantation temperature. The critical dose for the convers ion of the diamond structure into a disordered network and the migrating te mperature for nitrogen atoms in H-2(+) ion radiation-damaged diamond are fo und to be more than 1.3 x 10(17) H/cm(2) and 1200 degrees C, respectively. (C) 1999 Elsevier Science Ltd. All rights reserved.