Optical, spectral, and thermal analyses of InGaN/GaN near-ultraviolet flip-chip light-emitting diodes with different package structures.

We analyzed and compared the optical, spectral, and thermal characteristics of InGaN/GaN near-ultraviolet (NUV) flip-chip (FC) light-emitting diodes (LEDs) packaged on the board with dielectric/metal layers (DMB package), board with ceramic/metal layers (CMB package), and board with ceramic/metal layers and thermal tape (CMBT package) in the injection current range of 0-800 mA at 298 and 358 K. For the DMB packaged LED, the relatively high junction temperature was observed due to the inefficient heat dissipation, leading to the more optical output power drop and spectral shift. For the CMBT packaged device, it further dissipated heat at high currents where the performance of CMB packaged device was degraded. In comparison with the experimental results, the theoretically calculated temperature and stress distributions of the NUV FC LEDs with the DMB and CMB packages were also investigated by finite element method-based simulations. [ABSTRACT FROM AUTHOR]