InAlN/GaN MISHEMTs With 120 nm T-Shape Recessed Gates on Silicon With Excellent mm-Wave Noise Performance

Abstract

InAlN/GaN metal-insulator-semiconductor high electron mobility transistors (MISHEMTs) with a 120 nm T-gate and gate recess on a silicon substrate were fabricated. A thin 1.5 nm HfO <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{2}$</tex-math> </inline-formula> was prepared by plasma-enhanced atomic layer (PEALD) deposition as the gate dielectric. The high electron mobility transistors (HEMTs) exhibited a maximum drain current ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{dmax}}$</tex-math> </inline-formula> ) of 1.5 A/mm, a peak transconductance ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</i> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{mmax}}$</tex-math> </inline-formula> ) of 495 mS/mm, a cut-off frequency ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{T}}$</tex-math> </inline-formula> ) of 95 GHz, and a maximum oscillation frequency ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{max}}$</tex-math> </inline-formula> ) of 115 GHz. The fabricated MISHEMTs 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">$_{\text{min}}$</tex-math> </inline-formula> ) of 1.3 dB with an associated gain ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</i> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{a}}$</tex-math> </inline-formula> ) of 7.7 dB at 30 GHz, and NF <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{min}}$</tex-math> </inline-formula> of 1.7 dB and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</i> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{a}}$</tex-math> </inline-formula> of 6 dB at 40 GHz. These excellent results show the great potential of the InAlN/GaN-on-Si HEMTs in the application of millimeter wave (mm-Wave) low noise amplifiers (LNAs).