Rapid thermal annealed InGaN/GaN flip-chip LEDs

Nitride-based flip-chip (FC) light-emitting diodes (LEDs) emitting at 465 nm with Ni transparent ohmic contact layers and Ag reflective mirrors were fabricated. With an incident light wavelength of 465 nm, it was found that transmittance of normalized 300°C rapid thermal annealed (RTA) Ni(2.5 nm) was 93% while normalized reflectance of 300°C RTA Ni(2.5 nm)/Ag(200 nm) was 92%. It was also found that 300°C RTA Ni(2.5 nm) formed good ohmic contact on n⁺ short-period-superlattice structure with specific contact resistance of 7.8×10^-4 Ω·cm². With 20-mA current injection, it was found that forward voltage and output power were 3.15 V and 16.2 mW for FC LED with 300°C RTA Ni(2.5 nm)/Ag(200 nm). Furthermore, it was found that reliabilities of FC LEDs were good.