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

Abstract

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/H2 molar ratios and on growth directions. The critical boron concentration lied in the 6.5–17.0 × 1020at/cm3 range in the ⟨111⟩ direction and at 3.2 × 1021 at/cm3 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.