Richard B. Brown - Research
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Analysis and development of design styles for low power SOI circuits
Graduate Student Researcher: Rahul Rao

Gate leakage of an NMOS device as a function of Vgs and Vds

The tremendous growth in mobile and portable devices and applications has caused an enormous thrust for low-power circuit design. Chip power consumption (in active and standby mode) has steadily risen with technological advancements and there exists a need for novel circuit-level solutions for development of low power design. SOI technology provides performance benefits due to its myriad advantages, and is widely being used in high-performance designs. This work aims to investigate the applicability of SOI for design in the low-power application space and develop techniques to optimize SOI for low-power designs.

A dual-issue super-scalar microprocessor based on POWERPC architecture and the WIMS micro-controller have been designed and fabricated in bulk CMOS 0.18µm technology. An in-depth analysis of leakage currents and their dependencies on circuit, process and environmental conditions is currently being performed. Figure shows the gate leakage as a function of the gate-to-source and drain-to-source bias in an advanced SOI process. Techniques for quick and accurate estimation of leakage currents are being developed. Novel circuit-level techniques for minimizing the power consumption in standby mode are being developed.

 Future work involves an analysis of commonly used circuit families in SOI from a power perspective and development of circuit-level techniques for minimizing both leakage and active power in SOI. The applicability of these techniques to real world designs will be demonstrated by using these methods for the design of the POWERPC and the WIMS microcontroller in SOI technology. This work has been funded in part by the Semiconductor Research Corporation, the IBM Austin Center for Advanced Studies, and the Engineering Research Centers Program of the U.S. National Science Foundation under Award No. EEC-9986866.