In the never-ending quest to find new, more energy-efficient lighting technologies, light-emitting diodes (LEDs) have always held great promise. Like so many other technologies with great potential, making them cost-competitive has been the challenge. That may change with the announcement by one manufacturer that it will soon begin making LED chips on silicon wafers.
In August, Livermore, Calif.-based LED manufacturer Bridgelux announced it successfully applied LED chips to silicon and achieved high levels of lighting output, a result that bodes well for the low-cost, mass production of LEDs for consumer markets.
LEDs consist of semiconductor chips, made from Gallium nitride (GaN), which are applied to sapphire or silicon carbide. Applying them to silicon wafers could greatly reduce their cost.
However, the wafer application has been plagued by other problems, specifically cracking and bowing. Bridgelux claims to have solved these problems and achieved a lighting output that “has shattered its previous industry record.”
According to the company, the performance level of its silicon-wafer LEDs is comparable to sapphire-based LEDs. Specifically, the cool white LEDs showed efficiencies as high as 160 lumens per watt, and warm white LEDs showed efficiencies of 125 lumens per watt.
According to Bridgelux, applying the chips to silicon wafers could reduce the cost of LED production by as much as 75 percent. Silicon wafers are less expensive than sapphire or silicon carbide, and they are compatible with high-volume mass production by silicon-chip manufacturers. This development could pave the way for widespread adoption of LED lighting in homes and commercial buildings.
Bridgelux expects to have its first commercially available silicon wafer LEDs available for delivery to the market within the next two years.