History dependence of non-fully depleted (NFD) digital SOI circuits

In this paper we experimentally demonstrate that the switching speed of digital circuits built from Non-Fully Depleted (NFD) SOI MOSFETs show a time dependence. Using a very high-bandwidth setup and pulses as short as 1 nsec, the magnitude and range of this memory effect are determined. It is demonstrated that the propagation delay variations have switching-history, Vdd, and Leff dependence. The cause of this behavior is traced to the SOI MOSFET's floating body and the dynamic variations of its stored charge and potential.