Ultra-low-voltage MTCMOS/SIMOX technology hardened to temperature variation

Abstract

A novel multi-threshold CMOS (MTCMOS) circuit which offers the advantage of less variation in leakage current and delay time over a wide temperature range is described. It is shown that MTCMOS/SIMOX technology, which uses a SIMOX device and combines fully depleted low-threshold MOSFETs and partially depleted high-threshold MOSFETs, can reduce variation of circuit performance due to changes in the operating temperature. To evaluate the variation in circuit performance, models of the leakage-current and the delay-time including operating temperature are derived. Calculations using the models verify that the MTCMOS/SIMOX device with threshold voltages immune to temperature changes reduces the variation. This is also confirmed by an evaluation of a gate-chain TEG designed and fabricated with 0.25 μm MTCMOS/SIMOX technology.