Performance and reliability of wafer-bonded AlGaInP /mirror/Si light-emitting diodes

AlGaInP light emitting diode (LED) with a mirror substrate has been successfully fabricated by wafer bonding. The bonding technique using a metallic interlayer has been developed to eliminate handling the fragile, free-standing epilayers. Various structures of the mirror substrate have been studied, and a suitable structure of Au/AuBe/SiO2/Si is proposed. From the observation of the chip fabrication process, it was found that the SiO2 layer could isolate the stress causing from the Si substrate. The device performance of bonded LED is obviously far superior to that of the standard absorb-substrate LED. It exhibits normal p-n diode behavior with a low series resistance. Moreover, the emission wavelength of the bonded LED was independent of the injection current. The low forward series resistance and a good heat sink provided by Si substrate solve the joule heating inhering in conventional LED problem. Furthermore, the bonded LED with high reliability has been demonstrated.