Wafer bonding of 75 mm diameter GaP to AlGaInP-GaP light-emitting diode wafers

The AlGaInP/GaP wafer-bonded transparent-substrate (TS) light-emitting diod es (LEDs) have been shown to exhibit luminous efficiencies exceeding many c onventional lightning sources including 60 W incandescent sources. This pap er will demonstrate the feasibility of scaling wafer bonding technology to 75 mm. diameter wafers and some of the unique challengesassociated with thi s scaling. The quality and uniformity of bonding were characterized via sca nning acoustic microscopy, white light transmission measurements, full-wafe r mapping of parametric performance, and operating life tests. High bonding yields over large areas facilitate low-cost, high-volume fabrication of TS AlGaInP/GaP LEDs, and thus, further enable these devices to compete with o ther lighting sources.