Much of the heat generated by semiconductor devices tends to build up within the semiconducting layers, thus affecting the efficiency of the device. For example, an LED may consist of semiconductor layers arranged to emit light from a light-emitting surface. As they have become increasingly important in electronics and lighting devices, LEDs continue to be developed that have ever increasing power requirements. This trend of increasing power has created cooling problems for such devices. These cooling problems can be exacerbated by the typically small size of these devices, which may render heat sinks with traditional aluminum heat fins ineffective due to their bulky nature.
Additionally, such traditional heat sinks block the emission of light if applied to the light-emitting surface of the LED. Because heat sinks cannot interfere with the function of the semiconductor layers or the light-emitting surface, they are often located at the junction between the LED and a supporting structure such as a circuit board. Such a heat sink location is relatively remote from the accumulation of much of the heat, namely, the light-emitting surface and the semiconductor layer/
Chien-Min Sung (Tansui, Taipei County 251, TW) discovered that forming a diamond layer within the LED package allows adequate cooling even at high power, while at the same time maintaining a small LED package size. The maximum operating wattage of an LED may be exceeded by drawing heat from the semiconductor layers of the LED with a diamond layer.
Sung earned U.S. Patent 7,646,025
Additionally, in both semiconductor devices that emit light and those that don't, heat may be trapped within the semiconducting layers due to the relatively poor thermal conductivity of materials that often make up these layers. Also, crystal lattice mismatches between semiconductive layers slow the conduction of heat, thus facilitating further heat buildup.
Semiconductor devices have now been developed incorporating layers of diamond that provide, among other things, improved cooling properties to the device. Such layers of diamond increase the flow of heat laterally through the semiconductor device to thus reduce the amount of heat trapped within the semiconductor layers. This lateral heat transmission may thus effectively improve the thermal properties of many semiconductor devices. Furthermore, devices according to aspects of the present invention have increased lattice matching, thus further improving their thermal cooling properties. Additionally, it should be noted that the beneficial properties provided by diamond layers may extend beyond cooling.
More effective cooling can be achieved within a semiconductor device if diamond layers can be incorporated close to the semiconducting layers. One barrier to integration concerns the high dielectric properties of diamond materials, particularly those that have substantially single crystal lattice configurations. Optimum cooling conditions may be achieved if the diamond layer is within the conductive pathway of the semiconductor device, however such configurations have been difficult to achieve due to the dielectric properties of diamond. It has now been discovered that a conductive diamond layer can function as an electrode and be coupled to semiconductor layers and thus be within the conductive pathway of the device.
Additionally, by utilizing a conductive diamond layer as an electrode, LED devices can be constructed having a linear conductive pathway through the semiconductive layers between the electrodes. Many prior LED devices were constructed such that the conductive pathway from the n-type electrode was at a right angle to the conductive pathway from the p-type electrode. Such an "L" shaped conductive pathway caused electrons and holes to be oriented at right angles to one another, thus reducing the efficiency of the device. The linear conductive pathway according to aspects with nanodiamond layers causes electrons and holes to be oriented along the same linear pathway, thus improving the efficiency of the LED device, says Sung in his patent.
More effective cooling can be achieved within a semiconductor device if diamond layers can be incorporated close to the semiconducting layers. One barrier to integration concerns the high dielectric properties of diamond materials, particularly those that have substantially single crystal lattice configurations. Optimum cooling conditions may be achieved if the diamond layer is within the conductive pathway of the semiconductor device, however such configurations have been difficult to achieve due to the dielectric properties of diamond. It has now been discovered that a conductive diamond layer can function as an electrode and be coupled to semiconductor layers and thus be within the conductive pathway of the device.
Additionally, by utilizing a conductive diamond layer as an electrode, LED devices can be constructed having a linear conductive pathway through the semiconductive layers between the electrodes. Many prior LED devices were constructed such that the conductive pathway from the n-type electrode was at a right angle to the conductive pathway from the p-type electrode. Such an "L" shaped conductive pathway caused electrons and holes to be oriented at right angles to one another, thus reducing the efficiency of the device. The linear conductive pathway according to aspects with nanodiamond layers causes electrons and holes to be oriented along the same linear pathway, thus improving the efficiency of the LED device, says Sung in his patent.
