Heterogeneous integration of ultrawide bandgap semiconductors for radio frequency power devices
- Hong Zhou
- Min Zhou
- Mingjie Xiang
- Hehe Gong
- Guangjie Gao
- Chenlu Wang
- Yachao Zhang
- Kui Dang
- Zhihong Liu
- Jinfeng Zhang
- HangMing Zhang
- Yifan Wang
- Han Wang
- Mengwei Si
- Yuhao Zhang
- Yue Hao
- Jincheng Zhang
2025-11-19
Ultrawide bandgap (UWBG) semiconductors offer high critical electric fields and saturation velocities ideal for radio frequency (rf) devices, but achieving both shallow-level doping and high thermal conductivity ( k T ) in a single material remains difficult. We demonstrate a scalable, exfoliation-based layer-transfer process to heterogeneously integrate gallium oxide (Ga 2 O 3 ) thin films with shallow dopants onto high- k T aluminum nitride (AlN) substrates. This method obviates ion implantation and interfacial dielectric layers used in conventional approaches. A large conduction band offset (3.4 electron volts) at the Ga 2 O 3 /AlN interface improves electron confinement in the Ga 2 O 3 channel. T-gate rf power transistors achieve a maximum oscillation frequency of 90 gigahertz and output power densities of 4.6 watts per millimeter at 2 gigahertz and 4.1 watts per millimeter at 6 gigahertz—among the highest for UWBG devices. A minimal noise figure of 0.48 decibels at 8 gigahertz—among the lowest reported in this frequency range—further highlights the platform’s promise for next-generation rf applications.