In the power electronics/microelectronics, the substrate material, committed to chips for dissipation of heat to large area in order to preserve the reliability of the active components, is the most important material, especially when the requirement of higher power output has been increasing every day. For this purpose, diamond is considered as the best heat spreader that prevents the creation of points of excessive temperature on the active component (e.g. laser sub mounts, etc.). Our CVD diamond is the best candidate to be used as a heat spreader because of its outstanding thermal conductivity, low thermal expansion, and high electrical resistivity.