Vertical-conducting p-side-up GaN/mirror/Si light-emitting diodes by laser lift-off and wafer-transfer techniques

A p-side-up GaN/Ag/Au–Sn/Si light-emitting diode (LED) has been fabricated by a combination of laser lift-off and wafer-transfer techniques. The Ag/Au-Sn mirror structure was chosen to favor high optical reflectivity, low contact resistance with n-GaN, vertical conducting, and low-temperature (∼300 °C) wafer bonding. The GaN/Ag/Au–Sn/Si LED presented a maximum luminance intensity of 129 mcd (@ 20 mA) with a forward voltage of 3.3 V. The luminance intensity is over two times in magnitude as compared with that of the original planar GaN/sapphire LED. Under high current injection, the GaN/Ag/Au-Sn/Si LED also showed a more stable emission wavelength. This feature is attributed to the Si substrate providing a good heat sink. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)