Evaluation of growth sector orientation changes of high B doped high pressure and high temperature diamond by high resolution electron backscatter diffraction study

The orientation of growth sectors of highly B doped p+ high pressure and high temperature (HPHT) substrates were investigated by high angular resolution electron backscatter diffraction (HR-EBSD). The lattice rotation mapping images of the areas across the 〈111〉 growth sector boundaries were measured. The crystal orientation was found to be inclined approximately 0.03° for [001] to [-1-10], compared with the [-1-11] growth sector area at a given location. Other orientation inclinations were observed such as 0.02° for [001] to [110] and 0.025° for [001] to [1-10]. The same phenomena were confirmed for the other two crystals. Conventionally, it has been recognized that a HPHT-grown crystal is a perfect single crystal, however, our results indicate that "twin boundaries" are formed between the growth sectors for p+ HPHT substrates. To meet the requirements for the power device wafer specifications, the establishment of growth technology is desirable in the near future.