Apparatus and methods for characterizing floating body effects in SOI devices

Methods are described for characterizing floating body delay effects in SOI wafers comprising providing a pulse edge to a floating body and a tied body chain in the wafer, storing tied body chain data according to one or more of the floating body devices, and characterizing the floating body delay effects according to the stored tied body chain data. Test apparatus are also described comprising a floating body chain including a plurality of series connected floating body inverters or NAND gates fabricated in the wafer and a tied body chain comprising a plurality of series connected tied body devices to in the wafer. Storage devices are coupled with the tied body devices and with one or more of the floating body devices and operate to store tied body chain data from the tied body devices according to one or more signals from floating body chain.