Abstract
Recently, the micro-light-emitting diode has become a potential commercial device, which is integrated with functional module for widely applications, such as micro-display, micro-projector, mask-free photolithography, and optogenetics. In this research, a monolithic 450 nm GaN-based 64 × 64 micro-light-emitting diode arrays (μLEDA) with flip-chip bonding is demonstrated. To realize a high-quality μLEDA, this research has to deal with issues raised by area shrinkage and arrayed emitters. Area shrinkage results in increased series resistance and enhanced perimeter effect, while arrayed emitters result in optical crosstalk. Furthermore, the flip-chip boning technology is introduced for enhancing the extraction efficiency and improving heat dissipation. Underfilling is also added to the process to improve the stability of the devices. We delve into these problems and find appropriate countermeasures to raise the yield and uniformity of the μLEDA. The operation voltage at 100 μA (25 A/cm2) and leakage current at -5 V are 2.89 V and 41.62 pA, respectively. And the output power at 100 μA (25 A/cm2) and 20 mA (5 kA/cm2) could be achieved to 9.5 μW and 0.42 mW, respectively. In order to develop applications of active-matrix of μLEDA in the future, the flip-chip bonding technology must be investigated. In this thesis, we evaporated 6 μm-thick indium bumps and induced the relationship between the bump area and height. The bonding process is optimized by varying bonding force, temperature and time. The 120 × 120 indium bumps array is fabricated, which includes the daisy chains design for examining each of contact resistance is about 0.3 Ω and the yield is up to 100%. In summary, 450 nm GaN-based 64 × 64 μLEDA with flip chip bonding is demonstrated in this thesis. We believed that these technologies play an important role to make μLEDA be a potential candidate for portable micro-projector with lowest power consumption.