[paper] 3D integrated GaN/RF-SOI SPST switch

Frédéric Drillet, Jérôme Loraine, Hassan Saleh, Imene Lahbib, Brice Grandchamp, Lucas Iogna-Prat, Insaf Lahbib, Ousmane Sow, Albert Kumar and Gregory U'Ren 

RF Small and large signal characterization of a 3D integrated GaN/RF-SOI SPST switch 

International Journal of Microwave and Wireless Technologies, pp. 1–6, 2021.

*X-FAB France, Corbeil-Essonnes (F)

Abstract: This paper presents the radio frequency (RF) measurements of an SPST switch realized in gallium nitride (GaN)/RF-SOI technology compared to its GaN/silicon (Si) equivalent. The samples are built with an innovative 3D heterogeneous integration technique. The RF switch transistors are GaN-based and the substrate is RF-SOI. The insertion loss obtained is below 0.4 dB up to 30 GHz while being 1 dB lower than its GaN/Si equivalent. This difference comes from the vertical capacitive coupling reduction of the transistor to the substrate. This reduction is estimated to 59% based on a RC network model fitted to S-parameters measurements. In large signal, the linearity study of the substrate through coplanar waveguide transmission line characterization shows the reduction of the average power level of H2 and H3 of 30 dB up to 38 dBm of input power. The large signal characterization of the SPST shows no compression up to 38 dBm and the H2 and H3 rejection levels at 38 dBm are respectively, 68 and 75 dBc.

Fig: X-FAB 3D integration proposal cross-section (left) and the picture of a GaN coupon (right).

Acknowledgement: We would like to acknowledge the Nano2022 program for partially funding this work.

Supplementary material: The supplementary material for this article can be found at DOI: 0.101/1759078721000076