<i>W</i>-Band Graded-Channel GaN HEMTs With Record 45% Power-Added-Efficiency at 94 GHz
Jeong‐Sun Moon, Bob Grabar, Joel Wong, Chuong Dao, Erdem Arkun, Haw Tai, Dave Fanning, Nicholas C. Miller, Michael Elliott, Ryan Gilbert, Nivedhita Venkatesan, Patrick Fay
Abstract
We report the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$W$ </tex-math></inline-formula> -band large-signal power and efficiency performance of Ga-polar graded-channel (GC) AlGaN/GaN high-electron-mobility transistors (HEMTs) with a 50-nm gate-length mini-field-plate (FP) T-gate. The pre-matched GC GaN HEMT devices with on-chip pre-matching networks show a peak power-added efficiency (PAE) of 45% at 94 GHz at 2.1 W/mm associated power density. With de-embedding of the metal losses in the matching networks, the peak PAE at the GC GaN HEMT itself was estimated to be 50% at 94 GHz with a 2.2 W/mm power density. These efficiencies are the highest reported at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$W$ </tex-math></inline-formula> -band frequencies among all GaN HEMT technologies, including both Ga-polar and N-polar orientations. The power performance was facilitated by high extrinsic <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f_{T}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f_{\mathrm {MAX}}$ </tex-math></inline-formula> of 170 and 347 GHz, respectively, with a GC GaN HEMT structure and a mini-FP T-Gate.