Diamond/Ir/SrTiO3:: A material combination for improved heteroepitaxial diamond films

Heteroepitaxial diamond films with highly improved alignment have been realized by using the layer sequence diamond/Ir/SrTiO3 (001). In a first step, epitaxial iridium films with a misorientation <0.2 degrees have been deposited on polished SrTiO3 (001) surfaces by electron-beam evaporation. Using the bias-enhanced nucleation procedure in microwave plasma chemical vapor deposition, epitaxial diamond grains with a density of 10(9) cm(-2) could be nucleated on these substrates. The orientation relationship for this layer system is diamond(001)[100]parallel to Ir(001)[100]parallel to SrTiO3(001)[100]. The polar and azimuthal spread for the crystal orientation of a 600 nm thick diamond film is about 1 degrees in each case. For an 8 mu m thick diamond film a significantly improved alignment of 0.34 degrees (polar) and 0.65 degrees (azimuthal) has been measured. The latter values, which to the best of our knowledge are superior to those of all former reports about epitaxial diamond films on alternative substrates, indicate the high potential of the substrateIr/SrTiO3 for the realization of large-area single-crystalline diamond films. (C) 1999 American Institute of Physics. [S0003-6951(99)00805-0].