Reliability and consistency are extremely important characteristics of an LED. Any designer looking to design an LED into a lighting system should consider not only how the LED will perform on hour 1 but also on hour 1k, 10k and 100k. 

It is evident that most LED deterioration is due to poor thermal management. excessive heat at the junction can damage the crystal quality, the bond pads, and even alter the chemistry of a Phosphor or an encapsulant material thus making it less transparent. As a general rule of thumb, the more efficiently you can drive heat away from an LED, the more consistent and more reliable your lighting system will be. 

SemiLEDs patented MvpLED^TM design, maximizes the efficacy of any thermal management system by maximizing the heat transfer rate from the junction to the LED package. Many thermal designs are very good however if the substrate on which the LED structure is built is a poor conductor of heat, such as Sapphire or Silicon, then the overall efficacy of the system is in question. SemiLEDs uses a copper alloy as a base substrate thus eliminating the bottleneck effect. 

The effects of the efficient Copper alloy base layer of SemiLEDs LEDs can be felt in the lifetime and light quality of packaged chips producing white light. Packages using SemiLEDs LEDs as opposed to Sapphire based LEDs maintained initial CCT values over time. Packages using Sapphire based LEDs shifted CCT by more than 20% towards the blue end of the spectrum, while packages using SemiLEDs LEDs only shifted CCT by 2%. This is due to the heat effects on the phosphor chemistry.