Impact of Size Scaling in Cryogenic InGaAs/InP HEMTs for Low-Noise and High-Frequency Performance

This work investigates the impact of size scaling on the performance of cryogenic In<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> _x </i>Ga<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${}_{{1} -{x}}$</tex-math> </inline-formula>As/InP high electron mobility transistors (HEMTs) for low-noise and high-frequency applications. Two quantum-well heterostructures, with 75% and 80% indium content, are examined from 300 to 4 K, including devices with gate lengths down to 40 nm and gate widths down to 380nm. At cryogenic temperatures, the 80% indium channel achieves a record combination of high-frequency metrics <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}_{T} =622$</tex-math> </inline-formula>GHz, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}_{\text {MAX}} =733$</tex-math> </inline-formula> GHz, and low-noise indication factor <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$({I}_{D})^{1/2} / {g}_{m} = 0.17~({V}\cdot \text {mm}/\text {S})^{1/2}$</tex-math> </inline-formula> on the same device. This performance is enabled by heterostructure engineering, resulting in ultralow <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{\text {ON}} = 250~\Omega \cdot $</tex-math> </inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula>m. The 75% indium heterostructure instead demonstrates superior low-noise operation, with a minimum subthreshold swing SS = 8.5 mV/decade and a noise indication factor as low as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$({I}_{D})^{1/2} / {g}_{m} = 0.15~({{V}\cdot \text {mm}/\text {S}})^{1/2}$</tex-math> </inline-formula> at optimal device dimensions. These results highlight the potential of InGaAs/InP HEMTs in cryogenic low-noise amplifiers (LNAs), for qubit readout in future high-density quantum computing architectures.