Low-voltage transient bipolar effect induced by dynamic floating-body charging in scaled PD/SOI MOSFET's

An increased significance of the parasitic bipolar transistor (BJT) in scaled floating-body partially depleted SOI MOSFET's under transient conditions is described. The transient parasitic BJT effect is analyzed using both simulations and highspeed pulse measurements of pass transistors in a sub-0.25 μm SOI technology. The transient BJT current can be significant even at low drain-source voltages, well below the device breakdown voltage, and does not scale with technology. Our analysis shows that it can be problematic in digital circuit operation, possibly causing write disturbs in SRAM's and decreased retention times for DRAM's Proper device/circuit design, suggested by our analysis, can however control the problems.