Self-standing device-quality single-crystalline diamond films on vicinal (001) surfaces fabricated using microwave-plasma chemical-vapor-deposition method

Device-quality self-standing diamond films have been fabricated by growing sufficiently thick homoepitaxial films on high-pressure/high-temperature-synthesized (HPHT) Ib-type (001) and vicinal (001) diamond substrates with the microwave-plasma chemical-vapor-deposition (CVD) method. The HPHT substrates used were separated from the homoepitaxial layers with a laser cutting technique. Higher-quality thick films were more successfully obtained in the case of the vicinal substrates, compared with the case of the substrate without substantial off-angle, indicating advantages of vicinal (001) Ib substrates. In room-temperature cathodoluminescence (CL) spectra taken on both sides of the self-standing diamond films thus fabricated, strong free-exciton emissions were observed even at room temperature whereas no nitrogen-related CL peaks were detectable, which are often observed even from rather-thick homoepitaxial CVD diamond films grown on HPHT Ib substrates.