XJIPC OpenIR  > 材料物理与化学研究室
高总剂量水平双极器件剂量率效应及加速评估试验方法的研究
李小龙
Subtype博士
Thesis Advisor陆妩
2018-05-30
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline微电子学与固体电子学
Keyword双极晶体管 剂量率效应 低剂量率损伤增强效应 损伤机制 变温加速评估方法
Abstract

电离总剂量是航天电子系统辐射效应研究的重要问题,其中双极器件因其特有的低剂量率损伤增强(Enhanced low Dose Rate Sensitivity, ELDRS)效应,近年来已成为航天用双极器件抗电离总剂量效应发展重点突破的方向及难点问题。目前普遍接受的ELDRS效应随总剂量的变化趋势为阈值区、线性区和饱和区,且前期的研究认为较高总剂量下和更低剂量率(<10mrad(Si)/s)下ELDRS效应会趋于饱和。但最近几年的研究报道在此情况下仍出现增强的趋势,通过现有物理模型外推的方法并不能解释增强现象,而现如今国内外为进一步提高深空探测能力,高可靠性、长寿命的飞行器已成为当前航天任务的现实需求。与此同时,ELDRS效应与器件制作工艺极为相关,不同工艺线中的器件ELDRS效应差异极大,这也是导致双极器件抗总剂量效应水平难以评估的原因。因此,开展更高总剂量水平下的辐射损伤机制和评估方法研究对双极器件抗辐射加固及加速评估试验至关重要。鉴于上述双极器件总剂量效应及评估方法研究中存在的问题,本论文以不同类型的晶体管、集成电路以及特殊测试结构栅控晶体管为研究对象,对宽剂量尺度下双极器件的辐射损伤规律、评估方法的物理机制及加速评估试验方法的建立进行了比较系统全面的研究。在辐射损伤规律方面,研究表明,不同剂量率条件辐照时,双极器件在剂量0~200krad(Si)范围内存在明显剂量率效应,未见饱和趋势,通过对器件增强因子的表征可知,伴随剂量率降低增强因子增大,同时,随着辐照剂量的累积,双极器件对剂量率的敏感程度下降。结合温度和氢浓度对辐射响应的影响规律,揭示了复合-俘获机制是剂量率效应产生的关键因素,氢分子的堆积及碎裂机制是引起了剂量与剂量率效应相关性的主要原因。该研究结果为下一步的加速评估方法的建立提供了第一手的试验资料。在评估方法的物理机制方面,借助特殊测试结构栅控晶体管(GLPNP),分析了温度对缺陷电荷分布的响应机制。结合已有的变温加速评估试验方法和温度对缺陷间反应的影响,首次确定了变温评估方法的关键物理过程,包括低剂量阶段增强质子的直接释放和输运机制;中等剂量阶段降低氢二聚化机制,减小质子消耗;高剂量阶段抑制界面陷阱退火作用,增加质子间接释放机制,为加速评估试验方法的建立奠定了理论基础。在建立宽剂量尺度加速评估试验方法方面,不同剂量不同剂量率的温度辐照结果表明,剂量率对双极器件的退化模式影响不大,仅表现在敏感程度的差异。对比不同剂量条件的温度响应,随剂量的累积,氢的二聚化过程逐渐增强,导致器件损伤峰值向低温方向漂移。基于温度、剂量及剂量率对总剂量的影响机制,建立了剂量0~200krad(Si)范围的低剂量率变温加速评估试验程序,验证结果表明,该方法可以保守评估双极器件在低剂量率条件下的抗辐射能力,并且第一次将评估时间从8个月缩短至11小时。综上所述,本论文较系统、深入地研究了双极器件的剂量率效应,进一步完善和发展了双极器件总剂量效应的物理机制。并将研究结果用于建立变温加速评估试验方法的理论模型和宽剂量尺度的低剂量率加速评估试验程序。

Other Abstract

Enhanced low-dose-rate sensitivity (ELDRS), with more degradation occurring at low dose rate for bipolar transistors and integrated circuits (ICs), is considered to be one of the major concerns for total ionizing dose hardness-assurance testing intended for space missions. The most recent degradation models, it is generally accepted that the shape of degradation with ELDRS vary with the total dose, exhibiting threshold trend, linear trend, saturated trend. Further, previous studies suggest that the degradation of devices correspond to a saturated trend for the higher target dose or lower dose rate (<10mrad(Si)) irradiation conditions. However, the recent studies have reported that there is an enhancement phenomenon to occur in that case, but not the shape of saturation. In addition, high-reliability and long-life aircraft is necessary to improve the capability of deep-space exploration. Moreover, because of the variety in processing techniques for bipolar devices, such as oxide thickness, passivation materials, and the amount of hydrogen in packaging, radiation-tolerance testing of ELDRS parts can be complex and difficult. Thus, There must be an understanding of the mechanisms occurring for a higher target dose, to improve the radiation hardness assurance design and testing.Considering the issues related to the TID and hardness-assurance testing on the bipolar devices, the effects of dose rate on the radiation response of the bipolar transistors and linear ICs are examined for the higher target doses in this thesis.The experimental results submitted to various dose-rate irradiation, demonstrate that all of the experimental devices exhibit serious dose-rate effect, showing an enhanced degradation with the dose accumulation. Based on the analysis of the enhanced factor of the TID, the decreased dose rate results in enhanced degradation, and the damage sensitivity of the dose rate is related accumulated dose. Combining the influence of temperature and hydrogen concentration on radiation response, the key physical mechanism responsible for those effect are revealed, and the main reason for this correlation between dose and dose-rate effect is found to be the hydrogen molecules cracking mechanism. This research results provide the reference for the accelerated evaluation method.To fully understand the mechanism at play when the switched temperature irradiation applied, the specially designed gate-controlled lateral PNP transistors (GLPNP) that used to extract the interface traps (Nit) and oxide trapped charges (Not) are examined under various irradiation configurations. Based on analysis of the variations of Nit and Not, with temperature irradiation, suggest that the primary mechanisms for temperature switching irradiation (TSI) as an ELDRS test sequence are the accelerated liberation of protons and formation of Nit, which are key mechanisms in ELDRS. Firstly, the higher temperature accelerates the liberation of protons to form Nit, resulting in enhanced degradation at low dose level. Secondly, the moderate temperature limits protons loss in hydrogen dimerization and has the benefit of Nit buildup. Thirdly, noting that annealing effect and hydrogen dimerization are enhanced, further reduction in irradiation temperature suppress those effects. Therefore, with decreasing temperature irradiation, the Nit and Not at first higher temperature bring some positive influences on the evolution of Nit at subsequent low temperatures.Testing with temperature irradiations submitted to various dose rates, it is observed that the dose rate has influence on magnitude of the degradation, but not the shape of the curve trend. Moreover, the increased hydrogen dimerization, relative to the proton concentration, results in that the temperature corresponding to the peak degradation will move towards the lower temperature when the dose increases. Based on the impact of temperature, dose and dose rate on TID response of devices, the temperature switching irradiation as a ELDRS testing for a target dose of ~ 200krad(Si) has been first proposed in this thesis. This procedure has been experimentally verified by several types of devices, and provide sufficient bound to evaluate ELDRS. Further, it is first attempt to shorten irradiation time from 5 months to 11 h. To conclude, the total ionizing dose effects of the bipolar transistors and ICs are investigated, and extensive experimental research has been shown to develop the physical mechanism of ELDRS. Mover, applying those research results obtained from bipolar transistors and ICs with different irradiation conditions, the theoretical model of the temperature switching approach and the accelerated estimation of ELDRS procedure for higher target dose has been proposed in this thesis.

Pages126
Document Type学位论文
Identifierhttp://ir.xjipc.cas.cn/handle/365002/5471
Collection材料物理与化学研究室
Recommended Citation
GB/T 7714
李小龙. 高总剂量水平双极器件剂量率效应及加速评估试验方法的研究[D]. 北京. 中国科学院大学,2018.
Files in This Item:
File Name/Size DocType Version Access License
高总剂量水平双极器件剂量率效应及加速评估(3941KB)学位论文 开放获取CC BY-NC-SAView Application Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[李小龙]'s Articles
Baidu academic
Similar articles in Baidu academic
[李小龙]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[李小龙]'s Articles
Terms of Use
No data!
Social Bookmark/Share
File name: 高总剂量水平双极器件剂量率效应及加速评估试验方法的研究.pdf
Format: Adobe PDF
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.