题名星用纳米MOS器件的总剂量辐射效应与NBTI效应研究
作者余德昭
学位类别硕士
答辩日期2016-05-26
授予单位中国科学院大学
授予地点北京
导师余学峰
关键词MOSFET 辐射效应 NBTI 可靠性
学位专业微电子与固体电子学
中文摘要工艺尺寸缩小使得纳米MOS器件具有低功耗、高集成度、高工作频率等优点,可以满足星用电子系统高性能及小型化的迫切需求。然而,由于工作电压未随器件尺寸等比例缩小,纳米器件内部电场增强,其自身面临更为严峻的可靠性问题。MOS器件可靠性问题主要集中在与栅介质相关的可靠性上,包括热载流子注入(Hot Carrier Injection,HCI),经时击穿(Time Dependent Dielectric Breakdown,TDDB),负栅压温度不稳定性(Negative Bias Temperature Instability,NBTI)等问题。有研究表明,NBTI效应对纳米器件可靠性的影响将最终限制器件的使用寿命。不仅如此,应用在空间中的电子器件,面临高能粒子辐射及极端温度的严峻环境。纳米器件内部结构使得其具有不同于大尺寸器件的辐射效应、可靠性问题,同时辐射环境中的高能粒子引起的辐射损伤可能对其自身可靠性退化产生影响,对器件评估和性能预测带来挑战。因此,为了保障星用电子系统安全,急需对纳米器件的总剂量辐射效应、自身可靠性及二者的关联进行研究。国内外对辐射效应与NBTI效应的相互作用的报道仍然很少,相关课题的研究尤为迫切。本文以90nm和65nmCMOS工艺体硅器件为研究对象,开展了总剂量辐射效应及NBTI效应研究。首先开展了不同宽长比器件的辐照试验,获得了辐射损伤导致器件参数退化的规律,分析了辐射损伤机理,特别是窄沟器件参数退化严重的原因,以及PMOS器件关态电流退化的原因。在研究NBTI效应时,我们针对NBTI效应快速恢复的特性,设计了新的NBTI应力试验方法,避免了由于温度差异引起的测量误差,提高了结果的准确性。在此基础上,对纳米器件进行了NBTI试验,总结和分析了NBTI效应在沟道长度和宽度两个方向的退化规律并深入分析了NBTI损伤的机制。接着,通过对比纳米器件辐射损伤及NBTI引起的参数退化现象,分析了二者相关性和可能的关联。设计了辐照样品和未辐照样品NBTI应力对比试验,结果表明MOSFET总剂量效应与NBTI效应存在竞争关系,前者会减弱后者的退化,我们从损伤源、作用位置等方面分析了辐射损伤对器件NBTI效应的影响。研究结果具有一定的新颖性和现实意义。综上所述,本文针对星用纳米器件实际应用中面临的极端环境,开展其辐射效应及可靠性效应研究。建立了准确测试NBTI的方法,揭示了纳米器件辐射损伤及NBTI退化规律,分析了辐射损伤对NBTI的影响。研究结果对星用纳米器件的全面、准确评估和性能预测具有重要意义。
英文摘要With the continuous scaling down of the device, the reliability of semiconductor devices is becoming more and more serious. The reliability problems of MOS devices are mainly focused on the reliability of the gate dielectric, including HCI, TDDB and NBTI. Studies have shown that NBTI on Nano-device has been one of the most important limiting factors to circuit’s lifetime and will limit its life ultimately. Devices inmilitary and aerospace applications are subjected to extreme temperature and impact, while also facing a more severe radiation environment. That makes it difficult for life prediction. Interaction between the radiation effect and the NBTI effect is seldom studied. Research on related topics is particularly urgent.In this paper, the total dose irradiation and the NBTI test were carried out with 90nm and 65nm bulk devices. Total dose radiation effects of Nano-MOS devices are studied first. Results show that the radiation effect is still remarkable with significant narrow channel effect. The damage in NMOS isolation region caused by irradiation can even lead to ascending of trans-conductance. The gate-diode generation center density increased after irradiation, that made the current increased.It is necessary to choose the appropriate test method because of the fast recovery of the NBTI effect. In order to study the effect of NBTI, this paper improves the method of NBTI test, avoids the measurement error caused by temperature, and improves the accuracy of the result. Based on that, we carried on the experiment with 90nm and 65nm PMOSFETs. The degradation of NBTI effect in two directions of channel length and width is summarized and analyzed.It is pointed out that the short channel effect of NBTI is caused by higher defect concentration in gate oxide edge, and the stress in the STI and channel interface will cause more obvious degradation of the devices with smaller channel width.Oxide traps de-trapping and less of dangling bonds are the possible reasons for the fluctuation of stress degradation in small size devices. By comparing the NBTI degradation performance of irradiated and un-irradiated samples, the relationship between the total dose irradiation and the NBTI effect was analyzed. Whether from the source of damage or action position, there was a competitive relationship between total dose effect and NBTI effect, the former will weaken the latter's degradation.In summary,this paper studied on the radiation effect and reliability in view of the extreme environment faced in the practical application of Nano-devices. A method for the accurate measurement of NBTI is established.The radiation damage and NBTI degradation of Nano-devices are revealed.We analyzed the interaction between radiation effect and NBTI damage.The results have important significance for the comprehensive, accurate evaluation and performance prediction of Nano-devicesfor space application.
内容类型学位论文
源URL[http://ir.xjipc.cas.cn/handle/365002/4555]  
专题新疆理化技术研究所_材料物理与化学研究室
作者单位中国科学院新疆理化技术研究所
推荐引用方式
GB/T 7714
余德昭. 星用纳米MOS器件的总剂量辐射效应与NBTI效应研究[D]. 北京. 中国科学院大学. 2016.
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