Micro-Transfer Printing for Heterogeneous Integration of GaN and GaAs HEMTs

Here, we use the micro-transfer printing technique to demonstrate the device-level heterogeneous integration of two solid-state RF device technologies on the same interposer: GaN and GaAs high-electron-mobility transistors. The devices are released from their growth substrate using an epitaxial sacrificial layer while a thin polymer adhesion layer facilitates a strong bond between the target substrate and the compound semiconductor devices, allowing for post-transfer microfabrication processing. Transmission electron microscopy reveals no voids at the device/interposer interface and a polymer adhesion layer thickness of 5 +/- 2 nm. No significant degradation in dc electrical characteristics is observed after device transfer for either device technology. Improvement in thermal performance of GaN devices was demonstrated when transferred to a diamond substrate, even with the thin polymer adhesion layer at the device/interposer interface, illustrating a pathway for enhanced thermal management for GaN and other high-output-power density semiconductor technologies. The ability to combine various solid-state technologies at the device level with high density provides an approach to meet next-generation demands for RF and mixed-signal circuits.

Automated summary

In this study, the micro-transfer printing technique is used to integrate two solid-state RF device technologies, GaN and GaAs high-electron-mobility transistors, on the same interposer. The devices are released from their growth substrate using an epitaxial sacrificial layer, and a thin polymer adhesion layer is used to ensure a strong bond with the target substrate. The results show that the device/interposer interface has no voids, and the polymer adhesion layer has a thickness of 5+/-2 nm. There is no significant degradation in dc electrical characteristics after device transfer for either device technology. The ability to combine different solid-state technologies at the device level with high density offers a promising approach for meeting the demands of next-generation RF and mixed-signal circuits.