DC and RF characteristics of GaN HEMTs on glass substrates with a van der Waals AlN/glass interface

In this study, we report direct current and radio frequency (RF) characteristics of GaN high-electron-mobility transistors with a van der Waals (vdW) AlN/glass interface on glass substrates. Fluidic-assisted self-alignment transfer (FAST) and the integration processes are adopted to demonstrate the structure. Structural analysis confirms an abrupt AlN/glass vdW interface. Replacing the Si substrate of GaN-on-Si with an insulating glass improves off-state breakdown voltage from 81 to 138 V attributed to suppression of vertical substrate leakage. Moreover, maximum oscillation frequency (fmax) increases from 10.9 to 14.9 GHz due to the low-dielectric loss of glass, while the cutoff frequency remains nearly unchanged, confirming that intrinsic device properties are preserved after FAST and the integration processes. Port capacitance extraction from S-parameter measurements reveals that the drain-port capacitance decreases by approximately ×6, indicating that the fmax enhancement originates from suppression of pad-coupled parasitic and substrate loss. These results suggest that the proposed GaN-on-glass platform with the adhesive free, vdW AlN/glass interface can improve both breakdown voltage and RF performance.