JSSC 2011第9期MemorySRAM

Improvement of Read Margin and Its Distribution by Mismatch Self-Repair in 6T-SR

提出一种6T-SRAM失配自修复方案，通过局部电子注入提升读取裕量及其分布。

SNM提升20%，最小读取裕量提升70%，读取裕量分布减少20%

6T-SRAM读取裕量失配自修复局部电子注入不对称传输门

▸创新点1：采用不对称传输门晶体管设计，通过优化晶体管的尺寸和阈值电压，显著提高了6T-SRAM的读取裕量（SNM），实验数据显示SNM提升了20%，且不会影响写入性能。

▸创新点2：提出了一种后处理局部电子注入自修复技术，无需预先检测单元特性即可自动修复晶体管失配问题，从而将读取裕量的最小值提升了70%，同时将读取裕量的分布降低了20%。

▸创新点3：通过自修复功能实现了对传输门晶体管的动态调整，使得不对称偏移量达到传统方案的两倍，且无需额外的工艺步骤或单元面积开销。

▸创新点4：该方案在电路层面实现了高效的失配补偿，系统层面提升了SRAM的整体可靠性和稳定性，适用于高密度存储应用。

Abstract

A mismatch self-repair scheme in 6T-SRAM with asymmetric pass gate transistor by post-process local electron injection is proposed. Local electron injection is automatically and simultaneously achieved to e ither pass gate transistor that most increases the read margin for each cell without investigating its characteristics. The proposed asymmetric shift is twice as large as the conventional scheme without process and cell area penalty. Measurement results show 20% increase in SNM without write