Input Noise Voltage Below 1 nV/Hz1/2 at 1 kHz in the HEMTs at 4.2 K

Abstract

Specific High Electron Mobility Transistors (HEMTs) have been realized and characterized. At 4.2 K, with a drain-source current I ds of 1.55 mA and drain-source voltage V ds of 100 mV, the transistor has the following electrical characteristics: a transconductance and an output conductance of 69 and 3.8 mS, respectively, leading to an intrinsic voltage gain of 18; an input gate-source capacitance C gs of about 31 pF; and a gate leakage current less than 0.2 pA. An equivalent input noise voltage lower than 1 nV/Hz1/2 at 1 kHz has been achieved when I ds=1.55 mA at V ds=100 mV. Hence, our results show that the specific HEMTs should be a suitable transistor for future ultra-low noise deep cryogenic low-frequency high-impedance readout electronics.