Design, fabrication and characterizations of GaN-based blue micro light emitting diode(LED) arrays are reported.The GaN micro-LED array consists of 320×256 pixels with a pitch size of 30 fjym. Each pixel is 25×25 μm~2 in size, which is designed for backside emission and high density flip-chip packaging. The selected LED pixels being tested exhibit good uniformity in terms of turn-on voltage and reverse leakage current. The eficiency droop behavior and reliabilit.y behavior under high forward current stress are also studied. The micro-LED pixel shows improved reliability, which is likely caused by enhanced heat dissipation. Design, fabrication and characterizations of GaN-based blue micro light emitting diode (LED) arrays are reported. The GaN micro-LED array consists of 320 × 256 pixels with a pitch size of 30 fjym. Each pixel is 25 × 25 μm ~ 2 in size, which is designed for backside emission and high density flip-chip packaging. The selected LED pixels being tested exhibit good uniformity in terms of turn-on voltage and reverse leakage current. The eficiency droop behavior and reliabilit. y behavior under high forward The micro-LED pixel shows improved reliability, which is likely caused by enhanced heat dissipation.