Thermal Conductivity of Electrically Conductive Highly Boron Doped Diamond and its Applications at High Frequencies

Doping with boron during CVD synthesis allows for growth of electrically conductive diamond. Some important applications of boron doped diamond (BDD) include, chemically resistive electrodes, and electrically conductive thermal management material (~700 W/mK), whilst the conductivity allows the diamond to be cut by the electrical discharge machining method. Boron concentration influences thermal conductivity and electrical resistivity. Understanding how boron doping influences these properties is a key to successful integration of the material for various applications. As an electrically conductive heat spreader, thick, boron doped diamond with metallic conductivity (0.05 Ω-cm resistivity) is an ideal replacement for the commonly used metal/diamond configuration or other heat spreader such as copper, copper/refractory or copper laminate. Mounting of RF/Microwave devices on BDD heat spreader enables better isolation of the ground plane at below 1.5GHz, and in reduction of conductive losses at above 1.5GHz due to the increased skin depth.