Critical boron-doping levels for generation of dislocations in synthetic diamond

Defects induced by boron doping in diamond layers were studied by transmission electron microscopy. The existence of a critical boron doping level above which defects are generated is reported. This level is found to be dependent on the CH4/H-2 molar ratios and on growth directions. The critical boron concentration lied in the 6.5-17.0 x 10(20) at/cm(3) range in the < 111 > direction and at 3.2 x 10(21) at/cm(3) for the < 001 > one. Strain related effects induced by the doping are shown not to be responsible. From the location of dislocations and their Burger vectors, a model is proposed, together with their generation mechanism. (C) 2014 AIP Publishing LLC.