To investigate the gate oxide integrity for the silicon-on-insulator (SOI) wafer, we evaluated the time-dependent dielectric breakdown (TDDB) characteristic of gate oxide formed on SOI wafer with gate oxide thickness (T-ox) as a parameter. The TDDB characteristic was degraded with increasing the T-ox of gate oxide for the Sol wafer. The time to 50% failure of breakdown (T-BD) was shorter when T-ox was thicker than 7 nm in contrast to the gate oxide for the bulk silicon wafer. (C) 2003 Elsevier Science B.V. All rights reserved.