Interface features of the HPHT Ib substrate and homoepitaxial CVD diamond layer

•A higher stress region in the CVD diamond near the HPHT substrate was observed.•The region exhibited higher nitrogen content and different fluorescence properties.•Growth mechanisms of the diamond may play a crucial role in the interface feature.

This is a detailed study of the interface features of the HPHT Ib substrate and the homoepitaxial CVD diamond layer. Homoepitaxial diamond layers were prepared by a commercial type 30 kW dc arc plasma Jet CVD on (100) substrates with gas mixture of Ar/H2/CH4. The internal stress and the fluorescence properties of the cross-section of the single crystal diamond bulk were characterized with polarizer optical microscopy, micro-Raman spectroscopy, and photoluminescence, as well as DiamondView luminescence imaging. A higher stress region in the homoepitaxial diamond layer near the substrate with width about 15 μm was found exhibiting higher nitrogen content and presented different fluorescence properties. Studies on the surface morphology of the initial growth diamond indicated that the transformation of the surface morphology from growth hillocks to macrosteps, may play a crucial role in the interface feature.

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