Scaled-Footprint Ultra-Low Power Cryogenic InGaAs/InP HEMTs with Record-High Combination of Low-Noise and High-Frequency Performance

In this work we demonstrate cryogenic <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{In}_{\mathrm{x}}\text{Ga}_{1-\mathrm{x}}\text{As}/\text{InP}$</tex> HEMTs with highly scaled gate footprints, down to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$380 \times 40\ \text{nm}^{2}$</tex> for a single gate finger, and investigate the impact of footprint scaling on device performance. The 80% In channel devices show <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$f_{\mathrm{T}}=622$</tex> GHz and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$f_{\text{MAX}}=733$</tex> GHz together with a noise indication factor <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sqrt{I_{\mathrm{D}}}/g_{\mathrm{m}}=0.17 \sqrt{\mathrm{V}\cdot\text{mm}/\mathrm{S}}$</tex> at 4 K, which is a record-high combination of high-frequency and low-noise performance. The performance is enabled by heterostructure engineering, resulting in ultra-low <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R_{\text{ON}}=250\ \Omega\cdot\mu \mathrm{m}$</tex> together with a minimum subthreshold swing SS < 10 mV/decade. These results show that cryogenic III-V HEMT technology can provide excellent performance at scaled footprints for readout in future high-density quantum systems.