AlN/GaN/AlGaN-on-Si HEMT Achieving 1.3 W/mm at 5 V for 5G FR2 Handsets
Hanchao Li, Hanlin Xie, Qingyun Xie, Siyu Liu, Yue Wang, Yuxuan Wang, Kumud Ranjan, Yihao Zhuang, Xiao Gong, Geok Ing Ng
Abstract
This Letter reports a double heterostructure (DH) AlN/GaN/AlGaN-on-Si HEMT, which has been proposed, for low voltage (LV, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\le 5$ </tex-math></inline-formula> V) RF operation. The proposed transistor shows excellent DC (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\textit {dmax}} =1.9$ </tex-math></inline-formula> A/mm, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${g}_{\textit {mmax}} =0.66$ </tex-math></inline-formula> S/mm) and RF small-signal characteristics (<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>/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}_{\textit {max}} =145$ </tex-math></inline-formula>/195 GHz). Continuous-wave (CW) load-pull measurements at 30 GHz yield <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${P}_{\textit {sat}}$ </tex-math></inline-formula> of 0.6 (1.3) W/mm at V<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\textit {ds}}$ </tex-math></inline-formula> of 3.5 (5) V, and peak power-added efficiency (PAE) of 43% (42%). To the best of the authors’ knowledge, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${P}_{\textit {sat}}$ </tex-math></inline-formula> values are the highest reported for LV GaN-on-Si HEMTs in 5G FR2, despite the use of conventional alloyed contacts and a gate length (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${L}_{g}$ </tex-math></inline-formula>) of 120 nm. Furthermore, among published LV GaN-on-Si HEMTs, the proposed transistor achieves a desired combination of saturation velocity (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${v} _{\textit {sat}}$ </tex-math></inline-formula>) and knee voltage (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\textit {knee}}$ </tex-math></inline-formula>), which are critical factors for LV power amplification. The results reflect the promising potential of the proposed heterostructure to achieve high transmit power in 5G FR2 handsets.