Suppression of threshold voltage variation in MTCMOS/SIMOX circuit operating below 0.5 V

We describe a power-switch transistor for a multi-threshold CMOS/SIMOX circuit operating at extremely low supply voltage below 0.5 V. Power-switch transistors with a gate-body-connected variable-threshold MOSFET and a conventional MOSFET were fabricated and measured. The variable-threshold MOSFET suppressed the variation in threshold voltage and improved current drivability. Suppression of variation in gate delay time and improvement in the delay time were demonstrated at low supply voltage below 0.5 V.