Diamond based silicon-on-insulator structures

Total dose radiation hardness measurements were performed on SOI (silicon-on-insulator) test structures where the insulator was chemical vapor deposited (CVD) diamond in order to look at the fundamental radiation response of low-pressure CVD synthetic diamond materials for SOI applications. Silicon/diamond metal insulator semiconductor (MIS) capacitors were subjected to both cobalt-60 and 10 keV X-ray irradiation up to doses of 1×10⁷ rad(SiO₂) while under positive, negative, and zero bias conditions. One-MHz capacitance-voltage (C-V) measurements were performed to monitor the device threshold and flatband voltage shifts. In order to evaluate any time-dependent bias-temperature instabilities, all devices, after irradiation, were baked at 150°C with +5 V applied bias for five weeks. The measured results for flatband voltage shift versus time for 10 keV X-ray irradiation are presented. The diamond insulators used were free from extensive hole or electron trapping. This behavior is consistent with the high electron and hole mobility of the polycrystalline diamond insulator