Small GaN-based light-emitting diodes with a single electrode pad fabricated on a sapphire substrate

Small-scale GaN-based LEDs with a single electrode pad enjoying such properties as low cost, low series resistance, high efficiency and high yield were fabricated on a sapphire substrate by a novel and simple method. The devices present not only lower series resistance but higher light output power due to a specific n-contact design and better current spreading properties. Furthermore, higher ESD resistance (> −800 V at machine-mode operation) was demonstrated. The single-pad electrode of small-scale GaN-based LEDs has a chip size of 180 × 180 µm2, and showed a lower forward voltage of 3.15 V and 53.4% output power enhancement at 20 mA