Radiation hardness tests with a demonstrator preamplifier circuit manufactured in silicon on sapphire (SOS) VLSI technology

Samples of the preamplifier circuit, as well as of separate n and p channel transistors of the type contained in the circuit, were irradiated with gammas from 60 Co source up to an integrated dose of 3 Mrad (30 kGy). The VLSI manufacturing technology used is the SOS4 process of ABB Hafo. A first analysis of the tests shows that the performance of the amplifier remains practically unaffected by the radiation for total doses up to 1 Mrad. At higher doses up to 3 Mrad the circuit amplification factor decreases by a factor between 4 and 5 whereas the output noise level remains unchanged. It is argued that it may be possible to reduce the decrease in amplification factor in future by optimizing the amplifier circuit design further.