The study of Si/metal/GaN fusion bonding

GaN-based light-emitting diodes (LEDs) grown on sapphire substrates are integrated with Si by fusion bonding technique. GaN-based LEDs coated with Sn/Au are joined to Si coated with Ti/Au at 300 °C in a flowing nitrogen ambient for 30 min. Sapphire substrates are separated from the samples by laser lift-off (LLO) forming GaN-based LEDs/Sn/Au/Ti/Au/Si structures. Microscopy image, observed from the transparent GaN films, shows the uniform bonding interfaces free of air bubbles. The turn-on voltage of vertical GaN-based LEDs on Si decreases from 3.2v to 3.0v.