X-ray absorption near edge structure and extended X-ray absorption fine structure studies of P doped (111) diamond

The P dopant site control in diamond is critical to achieve high mobility n type channels and high concentration n+ layers for power device applications. In this study, the P doped diamond films grown by three institutes with varying hydrogen and dopant concentrations were analyzed by X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). By XANES, the film with high H concentration (4.0 × 10¹⁹ cm^-3) was estimated to show a higher peak intensity of 2147.7 eV than that of a low H concentration film. H was likely to be incorporated in the diamond as P-H at the substitutional sites under H rich growth condition. Another film showed considerably low peak intensities at 2147.7 and 2148.6 eV because of the "substitutional with H" and "substitutional" sites, respectively. The EXAFS result revealed that the first nearest neighbor distance is slightly shifted from the "substitutional" to "interstitial" site. The low P concentration film showed different types of energy profiles, particularly in the high energy region, indicating that dopant sites change with dopant concentration. Overall, the P dopant site is likely to be influenced by the machine system, H and P concentrations.