Microstructure evolution of boron doped homoepitaxial diamond films

We study the (004) diffraction peaks of (001) homoepitaxial diamond films (deposited by microwave plasma chemical vapor deposition) vs their boron content from 2 x 10(17) to 8 x 10(20) cm(-3). The lattice parameter calculated for the relaxed films slightly increases according to the linear Vegard's law up to 2.7 x 10(20) [B] cm(-3), then more rapidly with another Linear law. We ascribed this second law to an additional electronic contribution from the hole on the boron impurity band with a positive deformation potential around 16 eV. There is overall agreement between the deduced in-plane stresses and the Raman peak positions. The full width at half maximum of the diffraction peak is dominated by the concentration of residual defects which are lower in the film than in the substrate up to 10(20) [B] cm(-3). (C) 1998 American Institute of Physics.