The silicon-on-insulator (SOI) CMOS technology has a number of advantages over the standard bulk CMOS technology, such as no latch-up effect, high speed and low power. The fully depleted SOI (FD-SOI) technology provided by OKI Electric Industry Co., Ltd. is realizing the full features of the advantages with lowest junction capacitance. Test element group (TEG) structures of transistors were fabricated and irradiated with protons. The first results are presented. (c) 2007 Published by Elsevier B.V.