12-01 :: January 2012
at 3.15 volts, equivalent to 58% efficiency. These are outstanding values for 1 mm² chips at 350 mA. In combination with a conventional phosphor converter in a standard housing – in other words as white LEDs – these prototypes correspond to 140 lm at 350 mA with an efficiency of 127 lm/W at 4500 K.
“For these LEDs to become widely established in lighting, the components must get significantly che- aper while maintaining the same level of quality and performance,” says Dr. Peter Stauss, project manager at OSRAM Opto Semiconductors. “We are develo- ping new methods along the entire technology chain for this purpose, from chip technology to production processes and housing technology.” Mathematically speaking, it is already possible today to fabricate over 17,000 LED chips of one square millimeter in size on a 150mm wafer (6 inch). Larger silicon wafers could increase productivity even more; researchers have already demonstrated the first structures on 200mm substrates (about 8 inches).
The process diagram shows the production of a UX:3 chip on a silicon wafer. © OSRAM
OSRAM high-performance LED chips based on InGaN technology today are fabricated on wafers with a diameter of 6 inches. © OSRAM