UC Santa Cruz

Millions of mobile devices are being activated and used every single day. For such devices, energy efficient operation is very important; low-power operation enables not only long battery time but also improves energy efficiency of the servers that communicate with the mobile devices. However, reduced noise margin due to low-power operation and process variation due to nano-scale transistor feature sizes increase the number of errors in both mobile and server devices. Thus, low-power issues and reliability are strongly related.

This work focuses on reliable, low-power methodologies for SRAM memories. It is the first to consider SRAM cell optimization for power and reliability simultaneously. The main contributions are the following. To guide parametric hard faults, this work addresses energy optimality and yield considering redundant spare rows and columns. This work also describes a method for soft error tolerant low-power memory design using an architectural technique to avoid Multiple Bit Upset (MBU) at low voltages. Then methods using dynamic voltage scaling for soft error tolerant low-power memory designs are investigated.

This thesis results in the improvement of memory power consumption and in- creases the reliability of memory arrays. Using cell optimization, redundancy utilization, interleaving techniques, and adaptive dynamic voltage scaling, memory reliability is im- proved and power reduction is reduced by 10%-40% depending on the method applied without sacrificing error tolerance.