GaN-Based Power Flip-Chip LEDs With an Internal ESD Protection Diode on Cu Sub-Mount

The authors demonstrate the fabrication of 1 mm × 1 mm GaN-based power flip-chip light-emitting diodes (LEDs) with an internal electrostatic discharge (ESD) protection diode on Cu sub-mount. With the internal diode, it was found that forward voltage of the LED increased from 3.22 to 3.38 V while output power decreased from 366.5 to 273.9 mW when under 350 mA current injection due to the reduced light emitting area. It was also found that we can achieve a significantly better ESD robustness by building the internal diode inside the LED chip. Furthermore, It was found that 90% of the LEDs with internal diode survived with an applied reverse ESD surge of 12000 V and 25% of the LEDs can even endure 20000 V reverse ESD stressing.