High power and high reliability GaN/InGaN flip-chip light-emitting diodes

High-power and high-reliability GaN/InGaN flip-chip light-emittingdiodes (FCLEDs) have been demonstrated by employing a flip-chipdesign, and its fabrication process is developed. FCLED is composedof a LED die and a submount which is integrated with circuits toprotect the LED from electrostatic discharge (ESD) damage. The LEDdie is flip-chip soldered to the submount, and light is extractedthrough the transparent sapphire substrate instead of an absorbingNi/Au contact layer as in conventional GaN/InGaN LED epitaxialdesigns. The optical and electrical characteristics of the FCLED arepresented. According to ESD IEC61000-4-2 standard (human bodymodel), the FCLEDs tolerated at least 10,kV ESD shock have tentimes more capacity than conventional GaN/InGaN LEDs. It is shownthat the light output from the FCLEDs at forward current 350mA witha forward voltage of 3.3,V is 144.68,mW, and 236.59,mW at 1.0,Aof forward current. With employing an optimized contact scheme theFCLEDs can easily operate up to 1.0,A without significant powerdegradation or failure. The life test of FCLEDs is performed atforward current of 200,mA at room temperature. The degradation ofthe light output power is no more than 9% after 1010.75,h of lifetest, indicating the excellent reliability. FCLEDs can be used inpractice where high power and high reliability are necessary, andallow designs with a reduced number of LEDs.