Influence of diborane on the growth rate and phase stability of diamond films Original Research Article

The influence of the addition of high concentrations of diborane in the source gas on the growth of diamond films by chemical vapour deposition is investigated. For polycrystalline films grown on silicon, a decrease in the deposition rate is observed for boron concentration higher than B/C=6000 ppm, and a spurious amorphous carbon phase appears above B/C=10 000 ppm. For homoepitaxial growth on type Ib diamond, the deposition rate is nearly constant up to B/C=4000 ppm. With a higher boron concentration the films are polycrystalline. From the comparison of these two growth conditions shows we ascribed the decrease in the deposition rate, the appearance of a spurious phase and the loss of epitaxy to a modification of the plasma chemistry.