Optical, electrical, and mechanical reliability of 1700 PPI Micro-LED device

With the Micro-LED display device being widely used in the advanced display fields, the high reliability of device had become one of the key issues for applications of Micro-LED in many display fields such as VR/AR, portable displays, and flexible displays. The 512 × 384 green Micro-LEDs 0.39 in. array with 1700 PPI featuring a pixel pitch of 15 μm was integrated with the substrate by the AuIn flip-chip bonding. The average brightness, electroluminescence (EL) spectra, and I-V characteristics of the Micro-LED device aged at 85 °C/85 % RH for different time were measured to evaluate the optical and electrical reliability of the Micro-LED device. The mechanical reliability of the Micro-LED device after 336 h of aging was evaluated by shear test. The average brightness of the Micro-LED device decreased from 2.08 × 104 nit to 1.64 × 104 nit and the on-resistance of the Micro-LED device increased from 2.30 Ω to 2.82 Ω with the aging time increased to 336 h. The Micro-LED device was broken up with the shear strength value of 12.06 MPa, and the shear strength was only reduced by 8.25 % compared with that measured before aging.