Influence of oxygen addition on the crystal shape of CVD boron doped diamond

The development of diamond based devices for high power electronic applications requires the growth of thick heavily boron doped diamond. During the growth of CVD single crystals, the final form of the film depends on the different crystalline faces growth rate with respect to each others. Three parameters ( α , β and γ ) which correspond to the displacement speeds of the {111}, {110} and {113} faces, normalized to the {100} displacement speed can be used into a 3D crystal growth model in order to predict the final crystal morphology. This model has been applied with success to intrinsic diamond, and is extended here to the growth of boron doped diamond. It is found that the addition of diborane gas promotes the appearance of large {110} and {113} faces limiting the usable top surface area and generally leading to stress and consequently to crystal breaking‐up. By adding a small amount of oxygen (0.25%) to the feed gas, the {110} faces appearance can be inhibited and the crystal integrity preserved.