Fabrication and Characterization of a GaN-Based 320 × 256 Micro-LED Array ^*

Abstract

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 30μm. Each pixel is 25 × 25 μm2 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 efficiency droop behavior and reliability behavior under high forward current stress are also studied. The micro-LED pixel shows improved reliability, which is likely caused by enhanced heat dissipation.

3200 ppi Matrix-Addressable Blue MicroLED Display

“…The reverse current of a single pixel at −5 V has an astonishingly small value of 131 fA or 6.7 × 10 −7 A/cm 2 , presenting excellent electrical characteristics for a single pixel. This extremely low reverse leakage current is much lower than those of 5 pA at −5 V for the MicroLEDs with a size of 20 × 20 µm 2 [21,23], 1 pA at −3 V for the MicroLEDs with a size of 20 × 20 µm 2 [33], and 0.1 nA for the MicroLED with a size of 25 × 25 µm 2 by treating the sidewall with PECVD-SiO 2 [34]. Figure 5 illustrates the plot of EQE and wall-plug efficiency (WPE) as a function of logarithmic current density for a single pixel size of 5 μm for the 1920 × 1080 blue Mi-croLEDs.…”

The size and temperature effect of ideality factor in GaN/InGaN multiple quantum wells micro‐light‐emitting diodes

“…Figure 6 demonstrated the 80-μm device n factors at 1.9 and 2.1 V, and the inset indicated the size effect of n factors at 303 K. As we can see, the n value is more significant for larger size, and interestingly, all sizes exhibited an extremely low n as <1.9 for GaN micro-LED compared to other literature. 20,23,24 Here, are two suggested explanations for this phenomenon. One is the favorable ohmic contact between p-GaN and p-electrode can eliminate the metal-semiconductor junction in junction superposition theory; hence, the smallest n factor becomes near to 1.0.…”