Researchers at UCSB developed a scalable monolithic transfer process that uses selective electrochemical etching of a highly doped GaN sacrificial layer combined with wafer bonding to release and transfer fully fabricated micro-LED arrays onto silicon in a single step.
The researchers report that this breakthrough process eliminates laser lift-off and serial pick-and-place transfer, enabling low-damage, high-throughput heterogeneous integration of microLEDs devices for displays, optical interconnects, and sensing.
The researcher demonstrated fully-fabricated vertical microLED arrays with mesa sizes from 100x100 um2 down to 3x 3 um2, which were released and transferred to silicon carrier wafers in a single step, maintaining precise spatial registration without conventional laser lift-off or serial pick-and-place methods. It is reported that transferred devices exhibit low reverse leakage, uniform current injection and emission, and enhanced optical output due to the thin-film flip-chip architecture, with minimal degradation in spectral performance.
