Fig. 1. Schematic diagrams of AlGaInP-base LED epitaxial structure.

Fig. 2. Schematic diagrams of (a) conventional n-side-up AlGaInP LED structure and (b) n-AlGaInP contact LED.

Fig. 3. I-V behaviors of Sample D₅, ring intervals are 10−35 µm

Fig. 4. I-V behaviors of Sample A₁, B₁, C₁ and D₁ after annealing at 385 ℃ for 25 s.

Fig. 5. Contact resistivity as a function of doping concentration for different annealing conditions.

Fig. 6. SIMS depth profiles of Ni/Au/Ge/Ni/Au contact on n-(Al_0.27Ga_0.73)_0.5In_0.5P before annealing and after annealing.

Fig. 7. At the same N_D (a) ρ_c as a function of annealing temperature when the annealing time is 25 s; (b) ρ_c as a function of annealing temperature when the annealing temperature is 445 ℃.

Fig. 8. SEM micrographs showing the surface morphologies of ohmic contact (a) 445 ℃ for 25 s (b) 485 ℃ for 25 s.