Impact of Gate-Oxide Breakdown on Power-Gated SRAM

Abstract

This paper presents a detailed analysis on the impacts of various gate-oxide breakdown (BD) paths in column-based header- and footer-gated SRAMs. It is shown that with gate-oxide BD, the RSNM (Read Static Noise Margin) degrades, while the WM (Write Margin) improves in general. The effects of gate-to-source BD of cell transistors are shown to confine to the individual cell, while multiple cells suffering cell transistor drain-to-drain BD in a column could cumulatively affect VVDD (header structure) or VVSS (footer structure), thus influencing other cells in the same column. In particular, we show that the gate-oxide BD of the power-switches have server and even detrimental effects on the margin, stability, and performance of the SRAM array