Investigation of a GaN-on-Si HEMT optimized for the 5th-generation wireless communication

In this paper, AlGaN/GaN heterostructure high electron mobility transistors (HEMTs) have been fabricated on GaN-on-Si substrate. These devices were studied for the application of the 5th generation (5G) wireless communication. The geometric parameters such as gate length (Lg), cap length (Lcap) and gate-to-source distance (Lgs) are optimized so that the cut-off frequency reaches 38.8 GHz. It is found that decreasing Lg and Lgs can both improve drain current and peak transconductance (Gmmax). Highest drain current of 1 A/mm at Vg=2V and biggest Gmmax of 240 mS/mm was achieved. A fabricated device with Lg of 100 nm, Lcap of 300 nm and Lgs of 800 nm showed a fT of 38.8 GHz and a fMAX of 60 GHz at Vds=5V which can meet the requirement of the 5G application.