基于四值脉冲参数模型的单粒子瞬态传播机理与软错误率分析方法

Propagation Mechanism of Single Event Transient and Soft Error Rate Analysis Method Based on Four-value Pulse Parameters Model

随着工艺尺寸的不断缩小,由单粒子瞬态(Single Event Transient,SET)效应引起的软错误已经成为影响宇航用深亚微米VLSI电路可靠性的主要威胁,而SET脉冲的产生和传播也成为电路软错误研究的热点问题。通过研究SET脉冲在逻辑链路中的传播发现:脉冲上升时间和下降时间的差异能够引起输出脉冲宽度的展宽或衰减;脉冲的宽度和幅度可决定其是否会被门的电气效应所屏蔽。该文提出一种四值脉冲参数模型可准确模拟SET脉冲形状,并采用结合查找表和经验公式的方法来模拟SET脉冲在电路中的传播过程。该文提出的四值脉冲参数模型可模拟SET脉冲在传播过程中的展宽和衰减效应,与单参数脉冲模型相比计算精度提高了2.4%。该文应用基于图的故障传播概率算法模拟SET脉冲传播过程中的逻辑屏蔽,可快速计算电路的软错误率。对ISCAS’89及ISCAS’85电路进行分析的实验结果表明:该方法与HSPICE仿真方法的平均偏差为4.12%,计算速度提升10000倍。该文方法可对大规模集成电路的软错误率进行快速分析。

With the shrinking of feature size, soft errors due to Single Event Transient （SET） effect become the main reliability threat for aerospace deep sub-micron VLSI circuits, and the generation and propagation of SET pulse is also a hot issue in the study of soft error. Results of SET pulse propagation on logic chains show that the difference of rise and fall time of SET pulse can make the width of output pulse widened or lessened. The width and amplitude of SET pulse can determine whether it is electrically masked out. A four-value pulse parameters model is proposed to accurately characterize the shape of SET pulse, and then the LUT-based technique is combined with experiential equations to model the transmission process of SET. The proposed four-value pulse parameters model can model the effect of broadening or attenuation of SET pulse, and it has calculation precision improvement of 2.4% compared with single parameter model. This paper applies the graph-based error propagation probability analytic algorithm to estimate the logical masking in pulse propagation. The experimental results on ISCAS＇89 and ISCAS＇85 circuits show that the average deviation of this method and HSPICE simulation method is 4.12% and the calculation speed is 10000 times. This method can be used to analyze quickly the soft error rate of large scale integrated circuits.