(Invited) Wafer Bonding for the Manufacture of High-Brightness and High-Efficiency Light-Emitting Diodes

Abstract

Wafer bonding based layer transfer approaches permit the fabrication of powerful volume or surface-emitting light-emitting diodes (LEDs). Here we briefly review the basic approaches taken and show some exemplary results of our metal-bonded UX:3-LEDs with buried mirror and buried metallic current distribution for both polarities, . The overall device performance benefits from the UX:3 variant of our ThinGaN technology: (i) at a drive current of 350 mA, a 5 % brightness increase for blue and green emission; through improved interaction of chip and phosphor coating, a 10-20% brightness increase for white LEDs; (iii) when trebling the current from 350 mA to 1 A, the sublinear brightness increase, called droop, is reduced to only 15%; (iv) at a 1 A drive current, a drop in forward voltage of only 200 mV occurs.