DC AND NOISE PERFORMANCE OF C-HFET TRANSISTORS AT LOW DRAIN CURRENT DENSITIES

The results of measurements of complementary heterostructure field eff ect transistors (C-HFET) are reported. We have investigated the DC, AC and noise parameters of the devices as a function of the operating co nditions. In particular, we analysed their behaviour in the low power region at drain current densities less than 2 mA/mm and drain bias vol tages less than 2 V. It is shown that the transistors have excellent a mplification in this region. We found that the dominant 1/f noise, if measured as an equivalent noise charge on the input gate, is independe nt of the drain current and the drain bias voltage. Furthermore, the d ata show that the white serial noise increases with decreasing drain c urrent density and becomes a significant noise source at peaking times less than 25 ns and drain current densities less than 1 mA/mm only. A n extrapolation of the measurements shows that the total ENC of a C-HF ET input transistor with 25 mu m gate-width and 3 mu W power dissipati on will be about 25 electrons at zero detector capacitance with a slop e Delta(ENC)/Delta C-del around 440 electrons/pF.