基于再生长欧姆接触工艺的220 GHz InAlN/GaN 场效应晶体管

本文在蓝宝石衬底上研制了具有高电流增益截止频率(f_T)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(L_sd)缩小至600 nm。此外,采用自对准工艺制备了50 nm直栅。由于器件尺寸的缩小,V_gs= 1 V下器件最大饱和电流(I_ds)达到2.11 A/mm,峰值跨导达到609 mS/mm。小信号测试表明,器件f_T达到220 GHz、最大振荡频率(f_max)达到48 GHz。据我们所知,该f_T值是目前国内InAlN/GaN HFETs器件报道的最高结果。

fT=220 GHz InAlN/GaN HFETs with regrown ohmic contacts

Scaled InAlN/GaN heterostructure field-effect transistors (HFETs) with high unity current gain cut-off frequency (f_T) on sapphire substrate were fabricated and characterized. In the device, scaled source-to-drain distance (L_sd) of 600 nm was realized by metal organic chemical vapor deposition (MOCVD) based on regrow nonalloyed n -GaN Ohmic contacts. Moreover, a 50 nm rectangular gate was fabricated by self-aligned-gate technology. A high drain saturation current density (I_ds) of 2.11 A/mm @ V_gs= 1 V and a peak extrinsic transconductance (g_m) of 609 mS/mm were achieved in the InAlN/GaN HFETs. In addition, from the small-signal RF measurements, the values of f_Tand maximum oscillation frequency (f_max) for the device with 50-nm rectangular gate were extrapolated to be 220 GHz and 48 GHz. To our best knowledge, the value of f_T is the best domestic reported one for InAlN/GaN HFETs in China.