Recess-free enhancement-mode AlGaN/GaN RF HEMTs on Si substrate
Tiantian Luan, Sen Huang, Guanjun Jing, Jie Fan, Haibo Yin, Xinguo Gao, Sheng Zhang, Ke Wei, Yankui Li, Qimeng Jiang, Xinhua Wang, Bin Hou, Ling Yang, Xiaohua Ma, Xinyu Liu
Abstract
Abstract Enhancement-mode (E-mode) GaN-on-Si radio-frequency (RF) high-electron-mobility transistors (HEMTs) were fabricated on an ultrathin-barrier (UTB) AlGaN (<6 nm)/GaN heterostructure featuring a naturally depleted 2-D electron gas (2DEG) channel. The fabricated E-mode HEMTs exhibit a relatively high threshold voltage ( V TH ) of +1.1 V with good uniformity. A maximum current/power gain cut-off frequency ( f T / f MAX ) of 31.3/99.6 GHz with a power added efficiency (PAE) of 52.47% and an output power density ( P out ) of 1.0 W/mm at 3.5 GHz were achieved on the fabricated E-mode HEMTs with 1- µ m gate and Au-free ohmic contact.