Progress of diamond substrate development

Diamond has many excellent properties, such as wide bandgap, high carrier mobility, high breakdown voltage, high thermal conductivity, superior mechanical strength, and chemical stability among the well-known materials. In this talk, large size diamond development and application will be investigated. For heteroepitaxial single crystal diamond growth, preferred orientation Ir (001) film was deposited on sapphire substrate. Then bias enhanced CVD method was used to form diamond nucleation, on which a microwave plasma CVD(MPCVD) system was used to grow single crystal diamond. Then, tungsten atoms were introduced into MPCVD to grow high quality single crystal diamond on this sample. Thereafter, a laser machining technique was used to produce patterned trenches in diamond substrate, on which microchannels were achieved by epitaxial lateral overgrowth of diamond layer by MPCVD. In addition, we studied the enhanced heat spreading due to conduction followed by convective dissipation of a locally heated resistor mimicking a linear hot spot within electronic chips. The combined effect of conductive spreading and convective dissipation exhibited a significant cooling enhancement, which could be useful for GaN/diamond Composite Devices.