Microwave Low-Noise Performance of $0.17~\mu \text{m}$ Gate-Length AlGaN/GaN HEMTs on SiC With Wide Head Double-Deck T-Shaped Gate

Abstract

Microwave low-noise performance AlGaN/GaN HEMT on a SiC substrate with a wide head double-deck T-shaped gate has been reported. The HEMTs with 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">$L_{\mathrm { {g}}})$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.17~\mu \text{m}$ </tex-math></inline-formula> and source–drain spacing ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$L_{\mathrm { {sd}}})$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.5~\mu \text{m}$ </tex-math></inline-formula> exhibited a maximum extrinsic transconductance of 360 mS/mm, a current gain cutoff frequency ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f_{\mathrm { {T}}})$ </tex-math></inline-formula> of 50 GHz, a maximum oscillation frequency ( <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 149 GHz, and three-terminal breakdown voltage of 113 V. The device exhibited a minimum noise figure (NF <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathrm { {min}}})$ </tex-math></inline-formula> of 0.50 and 0.84 dB at 10 and 18 GHz, respectively, when biased at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\mathrm { {ds}}}= 5$ </tex-math></inline-formula> V and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$I_{\mathrm { {ds}}}= 140$ </tex-math></inline-formula> mA/mm, which is the lowest noise characteristics ever reported for the GaN-based T-shaped gate HEMTs with gate length larger than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.1~\mu \text{m}$ </tex-math></inline-formula> . This excellent noise performance is attributed to the reduction of the gate resistance resulting from a wide head T-shaped gate and the improved device characteristics.