基于SiC衬底AlGaN/GaN异质结材料研制具有高电流增益截止频率(fT)和最大振荡频率(fmax)的AlGaN/GaN异质结场效应晶体管(HFETs).基于MOCVD外延n+ GaN 欧姆接触工艺实现了器件尺寸的缩小, 有效源漏间距(Lsd)缩小至600 nm.此外, 采用自对准工艺制备了60 nm T型栅.由于器件尺寸的缩小, 在Vgs=2 V下, 器件最大饱和电流(Ids)达到2.0 A/mm, 该值为AlGaN/GaN HFETs器件直流测试下的最高值, 器件峰值跨导达到608 mS/mm.小信号测试表明, 器件fT和fmax最高值分别达到152 GHz和219 GHz.

Scaled AlGaN/GaN heterostructure field-effect transistors (HFETs) with a high unity current gain cut-off frequency (fT) and maximum oscillation frequency (fmax) were fabricated and characterised on an SiC substrate. In the device, the source-to-drain distance (Lsd) was scaled to 600 nm using regrown n+-GaN Ohmic contacts. In addition, a 60-nm T-shaped gate was fabricated by self-aligned-gate technology. A recorded drain saturation current density (Ids) of 2.0 A/mm at Vgs=2 V and a peak extrinsic transconductance (gm) of 608 mS/mm were obtained in the scaled AlGaN/GaN HFETs. Moreover, in the devices with a 60-nm T-shaped gate, the maximum values of fT and fmax reached 152 and 219 GHz, respectively.