Power Scaling of Graded-Channel GaN HEMTs With Mini-Field-Plate T-gate and 156 GHz f<sub>T</sub>
Jeong‐Sun Moon, Bob Grabar, Joel Wong, Chuong Dao, Erdem Arkun, Didiel V. Morales, Peter Chen, Christopher Malek, David Fanning, Nivedhita Venkatesan, Patrick Fay
Abstract
We report 60-nm gate-length graded-channel AlGaN/GaN HEMTs fabricated with a mini-field-plate T-gate. The devices exhibit an extrinsic f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> and f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MAX</sub> of 156 GHz and 308 GHz, respectively. At 60-nm gate length, the f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> *Lg of 9.4 GHz *μm is comparable to that of conventional scaled short gate-length AlGaN/GaN HEMTs. Due to minimal current collapse, the graded-channel GaN HEMTs demonstrated linear RF power scaling up to 5.5 W/mm at 30 GHz. This results in a record f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> T</sub> * power density product of 858 GHz * W/mm for Ga-polar GaN devices, indicating the promise of this device architecture for mmW amplifiers.