DC and noise performance of C-HFET transistors at low drain current densities

The results of measurements of complementary heterostructure field effect transistors (C-HFET) are reported. We have investigated the DC, AC and noise parameters of the devices as a function of the operating conditions. In particular, we analysed their behaviour in the low power region at drain current densities less than 2 mA/mm and drain bias voltages less than 2 V. It is shown that the transistors have excellent amplification in this region. We found that the dominant 1/f noise, if measured as an equivalent noise charge on the input gate, is independent of the drain current and the drain bias voltage. Furthermore, the data show that the white serial noise increases with decreasing drain current density and becomes a significant noise source at peaking times less than 25 ns and drain current densities less than 1 mA/mm only. An extrapolation of the measurements shows that the total ENC of a C-HFET input transistor with 25 μm gate-width and 3 μW power dissipation will be about 25 electrons at zero detector capacitance with a slope Δ(ENC)/ΔCdet around 440 electrons /pF.