Integration of GaN-LEDs with Heterogeneous Device Components by Epitaxil Film Bonding

Heterogeneous integration of the thin film gallium-nitride (GaN) LEDs of 2 μm thick and titanium oxide (TiO
₂
) waveguide were studied for biomedical and other potential applications. Epitaxial film bonding (EFB) of the thin film GaN-LEDs on the flat guest substrate of polyimide (PI)-coated silicon (Si) was first investigated and then the EFB of the thin film GaN-LEDs on the TiO
₂
waveguide was investigated. The thin film GaN-LEDs released from the mother substrate of Si were bonded on the PI-coated optical grating on the TiO
₂
waveguide at room temperature in the atmospheric environment with no adhesive. Good bond of the thin film GaN-LED on the optical grating was proved and integration of the thin film GaN-LED and waveguide by EFB was achieved. The spectrum peak shift of thin film GaN-LED bonded on the waveguide suggests that compressive stress to the active layer was released by the EFB of the thin film GaN-LED onto the waveguide. This study suggests that the EFB process is feasible to achieve integration of thin film devices on heterogeneous substrates implemented with various optical and electronic components.