65nm三阱CMOS静态随机存储器多位翻转实验研究

利用4种不同线性能量转换值的重离子对一款65nm三阱CMOS静态随机存储器(SRAM)进行重离子垂直辐照实验,将多位翻转图形、位置和事件数与器件结构布局结合对器件单粒子翻转截面、单粒子事件截面及多位翻转机理进行深入分析。结果表明,单粒子事件截面大于单个存储单元内敏感结点面积,单粒子翻转截面远大于单个存储单元面积。多位翻转事件数和规模的显著增长导致单粒子翻转截面远大于单粒子事件截面,多位翻转成为SRAM单粒子翻转的主要来源。结合器件垂直阱隔离布局及横向寄生双极晶体管位置,分析得到多位翻转主要由PMOS和NMOS晶体管的双极效应引起,且NMOS晶体管的双极效应是器件发生多位翻转的主要原因。

Experimental Research of Multiple Cell Upsets in 65 nm Triple-well CMOS Static Random Access Memory

The irradiation tests were performed in a 65 nm triple-well CMOS static random access memory (SRAM) in normal incident angle by using four kinds of heavy ions with different linear energy transfer (LET) values.The single event upset (SEU) cross sections in upsets and in events and the main physical mechanisms of multiple cell upsets (MCUs) were investigated by combining MCUs pattern, position, and counts with the memory cell array layout.The results show that the SEU cross section in events is larger than the area of sensitive nodes in a memory cell while the SEU cross section in upsets is much larger than the area of a cell.The SEU cross section in upsets is larger than SEU cross section in events because of the significant increase in MCUs amount and order, and MCUs become the main source of SEU in SRAM.Moreover, considering of the vertical well isolation layout and the position of parasitic lateral bipolar transistors, most MCUs are induced by parasitic bipolar effect of PMOS and NMOS, of which the parasitic bipolar effect of NMOS is the main cause of MCUs.