CHARACTERISTICS OF GAAS COMPLEMENTARY HETEROJUNCTION FETS AND C-HFET-BASED AMPLIFIERS EXPOSED TO HIGH PROTON FLUENCES

Test results with GaAs CHFETs and CHFET-based monolithic preamplifiers irradiated with up to 5 x 10(14) p/cm(2) are reported. The DC and noi se characteristics of all transistors were measured before and after i rradiation. Additionally, measurements on the DC and AC characteristic s of monolithic preamplifiers in CHFET-technology were performed. Afte r the irradiation with 5 x 10(14) p/cm(2) all devices are fully functi onal and show normal behaviour. For a pixel detector with a capacitanc e of 150 fF connected to an amplifier with an input transistor of 25 m u m gate width operating with a drain current density of 0.25 mA/mm, t he extrapolated ENC increases from 100 to 120 electrons for a peaking time of 25 ns. In this region of operation, the gate current is still in the order of nA. All measurements of the FETs were performed in the low-power consumption region with drain current densities less than 2 mA/mm.