WAFER BONDING OF 50-MM DIAMETER GAP TO ALGAINP-GAP LIGHT-EMITTING DIODE WAFERS

The feasibility of wafer bonding 50-nm diameter wafers consisting of G aP-AlGaInP Light-emitting diode epitaxial films to Cap substrates is d emonstrated. Wafer bonding over the entire wafer area is achieved whil e maintaining optical transparency and low-resistance electrical condu ction at the wafer-bonded interface. Using this technique, visible-spe ctrum transparent-substrate GaP-AlGaInP/GaP light emitting diodes (LED s) are fabricated across an entire 50-mm wafer with typical operating voltages <2.1 V at 20 mA and twice the flux of absorbing-substrate GaP -AlGaInP/GaAs LEDs. This large-area wafer-bonding method is further sh own to be capable of producing very high efficiency emitters, with an external quantum efficiency of 23.7% (300 K, 20 mA, de) at 635.6 nm. ( C) 1996 American Institute of Physics.