Single-Power-Supply Compatible Cryogenic In0.8Ga0.2As Quantum-well HEMTs with Record Combination of high-frequency and low-noise performance for quantum-computins applications

We present
$L_{g}=45$
nm E-mode cryogenic In
$0s\text{Ga}_{02}\text{As}$
quantum-well (QW) HEMTs with the record combination of high-frequency and low-noise characteristics. The fabricated devices exhibited a true E-mode operation, the best balance between
$f_{T}\simeq 662$
GHz and
$f_{mm}\simeq 65_{\sim}^{\gamma}$
GHz, and the lowest
$\sqrt{I_{D}}/\mathrm{g}_{\mathrm{m}}=0.176$
at 4 K. Besides, we investigated the temperature-dependent behavior. Three-layer model indicated that the reduction of
$\rho_{barrier}$
was critical to lower
$R_{s}$
at 4 K. According to the delay time analysis, the improvement
$\text{of}f_{T}$
was mainly due to the mitigation of the extrinsic channel charging delay, arising from the enhanced carrier transport at 4 K.