Radiation tolerant direct-coupled MISFET logic on InP

High-dynamic-range n-channel InP MISFET direct-coupled FET logic (DCFL) ring oscillator (RO) and inverter integrated circuits employing gate metallization lengths of 3.0 µm and exhibiting minimum observed propagation delay per stage tpd= 62 ps and minimum observed power delay prduct Ptpd= 22 fJ have been fabricated on Fe-doped semi-insulating substrate material. Preliminary total dose irradiation results on these RO structures as well as on InP CCD and discrete MISFET samples indicate that, under present test conditions, no changes in the performance of these devices can be attributed to the radiation flux to gamma doses as high as 10⁸rad and neutron doses as high as 1.7 × 10¹³neutrons per cm².