300-GHz InAlN/GaN HEMTs With InGaN Back Barrier

Abstract

This letter reports lattice-matched In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.17</sub> Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.83</sub> N/GaN high-electron-mobility transistors on a SiC substrate with a record current gain cutoff frequency (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> ) of 300 GHz. To suppress the short-channel effects (SCEs), an In0.15Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.85</sub> N back barrier is applied in an InAlN/GaN heterostructure for the first time. The GaN channel thickness is also scaled to 26 nm, which allows a good immunity to SCEs for gate lengths down to 70 nm even with a relatively thick top barrier (9.4-10.4 nm). In a 30-nm-gate-length device with an on-resistance (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> ) of 1.2 Ω · mm and an extrinsic transconductance (g <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m.ext</sub> ) of 530 mS/mm, a peak fa of 300 GHz is achieved. An electron velocity of 1.37-1.45 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> cm/s is extracted by two different delay analysis methods.