Hf 0.5 Zr 0.5 O 2 -Based Ferroelectric Gate HEMTs With Large Threshold Voltage Tuning Range

AlGaN/GaN high-electron-mobility transistors (HEMTs) with Hr _0.5 Zr _0.5 O ₂ ferroelectric gate stacks exhibiting significant ferroelectric switching for threshold voltage control are experimentally demonstrated. Ferroelectric gate HEMTs (FeHEMTs) with large threshold voltage tuning range of 2.8 V were obtained, with an on/off ratio of $\sim {10}^{{{5}}}$ based on a GaN-channel HEMT structure suitable for RF applications. Improved subthreshold performance has also been achieved compared to conventional MIS-HEMTs, with reduction in average sub-threshold swing (SS _avg ) by a factor of 2. As a consequence of the significant ferroelectric polarization achieved on AlGaN/GaN heterostructures, Hr _0.5 Zr _0.5 O ₂ based ferroelectric gate AlGaN/GaN HEMTs appear promising for nonvolatile and reconfigurable RF and microwave applications.