Diamond heat spreaders for high power devices with integrated temperature sensors

The use of a polycrystalline diamond film as a heat spreader in a laser diode array device was optimized with the three dimensional FEM software ABAQUS. A decrease in the thermal resistance of the device of nearly 50% could be achieved. A structured metallization was produced on top of the diamond to address each laser diode separately. Between the metallization strips, one thermistor per gap was inserted by doping the diamond film with boron by ion implantation. For calibration of these thermistors, their R(T) characteristics were investigated. In comparison with commercially available thermistors based on silicon or platinum, these thermistors showed a higher temperature coefficient of resistance and thus higher sensitivity. Additionally, the absolute resistance values were in a practicable range. This offers the possibility for industrial use. With the investigated temperature sensors, one can detect a wavelength shift of the emitted laser diode light of less than 0.1 nm due to a change of temperature