Evaluation of RF and Logic Performance for 80 nm InAs/InGaAs Composite Channel HEMTs Using Gate Sinking Technology

80-nm-gate In_0.7Ga_0.3As/InAs/In_0.7Ga_0.3As composite channel high-electron mobility transistors (HEMTs) fabricated using platinum (Pt) buried gate as the Schottky contact metal were evaluated for RF and logic application. After gate sinking at the 250degC for 3 minutes, the device exhibited a high g_m value of 1590 mS/mm at V_d = 0.5 V and the current gain cutoff frequency f_T was measured to be 494 GHz. The intrinsic gate delay time was calculated to be 0.78 psec at supply voltage of 0.6 V. This is the highest f_T achieved for 80 nm gate length HEMT devices. These superior performances are attributed to the reduction of distance between gate and channel, and the reduction of parasitic gate capacitances during gate-sinking process.