Correlated Kelvin-probe force microscopy, micro-FTIR and micro-Raman analysis of doping anisotropy in multisectorial boron-doped HPHT diamonds

Boron-doped diamond single crystals of cubo-octahedral habit have been obtained by temperature gradient method at high pressures and high temperatures (HPHT) in Fe-Al-B-C system, and multisectoral plates of different orientations have been produced. Spatial distribution of uncompensated boron impurity and surface potential through the interfaces of different growth sectors of diamond plates have been studied by scanning Fourier transform infrared (FTIR) and Raman micro-spectroscopy, as well as scanning spreading resistance microscopy (SSRM) and Kelvin-probe force microscopy (KPFM). FTIR mapping showed strongly non-uniform growth-sector dependent distribution of uncompensated boron impurity gradually decreasing in a sequence {111}->{110}-> {113} -> {001} from ~7 . 10(18 )cm(-3) down to 2 . 10(17 )cm(-3). Micro-Raman mapping is used to reveal the submicron distribution of structural quality and boron content through the interfaces of different growth sectors. The inter-sectoral jumps of the surface potential in the axial and radial directions of the growth sectors were studied by KPFM, their theoretical estimates are obtained, and the features of the band structure of the inter-sector interfaces are revealed. A high level of structural perfection of inter-sectoral boundaries without electrically active defects is demonstrated.

Automated summary

By using various microscopes, the interface characteristics of boron-doped diamond single crystals in different growth sectors were studied. The distribution of boron impurities and the structural quality showed significant differences among different sectors, while the inter-sectoral boundaries demonstrated a high level of structural perfection.