中文摘要：

在蓝宝石衬底上研制了具有高电流增益截止频率（fT）的InAlN／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600nm．此外，采用自对准工艺制备了50nm直栅．由于器件尺寸的缩小，Vgs=1V下器件最大饱和电流（Ids）达到2．11A／mm，峰值跨导达到609mS／mm．根据小信号测试结果，外推得到器件的fT和最大振荡频率（fmax）分别为220GHz和48GHz．据我们所知，该fT值是目前国内InAlN／GaNHFETs器件报道的最高结果．

英文摘要：

Scaled InA1N/GaN heterostructure field-effect transistors （HFETs） with high unity current gain cut-off frequency （fr） on sapphire substrate were fabricated and characterized. In this device, scaled source-to-drain dis- tance （Lsd） of 600 nm was realized by metal organic chemical vapor deposition （MOCVD） based on regrow non- alloyed n ＋ -GaN Ohmic contacts. Moreover, a 50 nm rectangular gate was fabricated by self-aligned-gate technolo- gy. A high drain saturation current density （lds） of 2.11 A/mm @ Vgs = 1 V and a peak extrinsic transconduct- ance （gm） of 609 mS/mm were achieved in the InA1N/GaN HFETs. In addition, from the small-signal RF meas- urements, the values offT and maximum oscillation frequency （fmax） for the device with 50-nm rectangular gate were extrapolated to be 220 GHz and 48 GHz. To our best knowledge, the value offT is the best reported one for InAIN/GaN HFETs in China.