ELO SOI technology for radiation hard devices

It is demonstrated experimentally that thin SOI structures with a predetermined oxide pattern can be made by ELO (epitaxial lateral overgrowth) technology and etchback. It is also demonstrated experimentally that these ELO SOI structures can support MOS devices to a reasonably high level of radiation. At a total dose of 10⁶ rad(SiO₂), the threshold voltage shift was only -0.17 V, the subthreshold slope change was only 16 mV/decade, and degradation of saturated transconductance was only 4%. At 1×10⁷ rad(SiO₂), the threshold voltage shift was -0.25 V, the subthreshold slope change was 50 mV/decade, and degradation of saturated transconductance was 18%. This degradation and hence degradation of the device performance at high total dose is due to interface state buildup as a result of irradiation