总剂量辐射下双极型运放效应统计特性分析

Statistical Analysis of Bipolar Operational Amplifier Under Total Dose Radiation

分析了国产运算放大器LM124的总剂量辐射效应统计规律。基于同一批次80个样本辐照前和100 Gy、200 Gy、500 Gy、1 000 Gy、1 500 Gy五个总剂量点辐照后的实验数据进行了分析,发现LM124的输入偏置电流退化呈对数正态分布特性,中位数随总剂量在3.6~7 nA范围内线性变化,总剂量增大,参数分散性增大。辐射损伤与初值存在线性正相关性,给出了参数的计算方法。100~1 500 Gy五个总剂量点线性系数α分别为0.24、0.31、0.5、0.77、1.07,α随总剂量的变化也呈线性。从物理上解释了初值依赖性的机理,即EB结上方氧化层质量决定了器件总剂量辐照响应的差异性(初值依赖性)。该研究成果可以有效支撑基于LM124电路或者整机的辐射可靠性定量评估,对双极型器件的总剂量效应加固筛选具有参考价值。

Based on the experimental data of same batch 80 samples before irradiation, and after 100, 200, 500, 1 000, 1 500 Gy total dose irradiation, the statistical law of a domestic operational amplifier LM124 under total dose irradiation was analyzed. A logarithmic normal distribution characteristics of input bias current variation was found, and the median input bias current changed within 3.6~7 nA linearly under irradiation. Also, the variation increased simultaneously with total dose. A positive linear correlation between the radiation damage and the initial value was obtained with the calculation method of the parameters. The linear coefficient(α) of the five total dose points from 100 to 1 500 Gy was 0.24, 0.31, 0.5, 0.77 and 1.07, respectively, and α showed a linear increment with the total dose. The mechanism of initial value dependence was physically explained, that is, the quality of oxide layer above EB junction determined the total dose irradiation response of the device(initial value dependence). The research results could effectively support the quantitative evaluation of radiation reliability for circuit or system based on LM124, and had a reference value for the total dose effect reinforcement screening of bipolar devices.