【作者】 孙鹏；

【导师】 杜磊；

【作者基本信息】 西安电子科技大学 ， 材料物理与化学， 2013， 博士

【摘要】 工作于太空中的电子元器件由于其环境特点会受到空间粒子的辐射作用。在辐射作用下，器件的性能下降，使用寿命也会减少。器件受到辐射作用后的性能下降源于器件内部材料的退化，并最终导致器件的失效。随着半导体工艺的进步，电子元器件持续小型化，集成电路封装不断密集化，导致器件关键参数的退化，从而增加了器件的失效概率。另一方面，器件尺寸的减小也会引起某些新效应，这些新效应会间接影响器件的可靠性。因此，有必要对太空环境中器件的辐射退化以及产生的新效应进行灵敏表征，从而对器件的整体可靠性进行评估。本文系统地研究了电子元器件辐射退化的物理机理，深入研究了MOS器件以及双极器件的辐射退化机理，并给出了对以上两种器件辐射退化的灵敏表征方法，除此之外，本文还对超深亚微米MOS器件的单粒子新效应进行了研究，重点研究了电荷共享这一新机理和多位翻转这一新效应，并对原有的电荷收集模型进行了修正，使其适用于超深亚微米MOS器件。本文具体的研究成果以及创新点如下：（1）对双极器件辐射作用后的参数变化进行了分析，结合双极器件辐射退化的物理机理，建立了双极器件辐射退化的噪声表征模型，并通过实验进行了验证。实验结果证实了模型的正确性，结果还表明，与电学参量相比，噪声参量的灵敏度更高，在电学参量变化率为3%左右的情况下，噪声参量的变化率高达2500%。因此，利用噪声参量可以对双极器件的辐射损伤进行进行灵敏表征。（2）对双极器件的电离辐射效应和位移辐射效应进行了研究，发现两种辐射效应的产生机制并不相同，并通过实验对两种效应进行了区分。结果表明，双极器件中的关键部位，即p-n结二极管的反向电流的变化可以很好的表征电离辐射效应，而其在某一固定电流处的正向电压的变化则可以很好的表征位移辐射效应。模型和实验结果均表明，在低剂量情况下，电离辐射效应占主导地位，随剂量增大，位移辐射效应所占的比例逐渐上升。（3）对MOS器件辐射退化的物理机理进行了研究，分别建立了MOS器件辐射退化模型以及辐射退化的噪声表征模型，并通过实验对模型进行了验证。实验结果验证了模型的正确性，发现氧化层陷阱电荷和界面陷阱电荷的数量在不同剂量下会产生饱和现象，其中界面陷阱电荷数量先产生饱和。结果还表明，当MOSII电子元器件辐射退化灵敏表征方法研究器件受到辐射作用时，其噪声参量的变化程度远大于电学参量的变化程度，因此，可以利用噪声参量对器件的辐射退化进行表征。（4）对MOS器件辐射作用前的1/f噪声特性进行了分析，发现辐射作用前的1/f噪声对MOS器件的潜在缺陷可以起到很好的表征作用。建立了基于辐射作用前1/f噪声的MOS器件潜在缺陷表征模型，并通过实验进行了验证。结果表明，MOS器件辐射作用后的阈值电压漂移量与辐射作用前的1/f噪声幅值成正比，因此，该模型有助于利用1/f噪声参量来表征MOSFET内部潜在缺陷的数量和严重程度。（5）对超深亚微米MOS器件的单粒子新效应进行了研究，发现了电荷共享这一新机理和多位翻转这一新效应。针对现有电荷收集模型无法应用于超深亚微米器件的情况，在原有模型的基础上提出了新模型，利用新模型对90nmMOS器件的电荷收集情况进行了模拟，并利用TCAD模拟软件进行了验证。结果表明，与原有模型的模拟结果相比，新模型的模拟结果与TCAD的模拟结果更为相近，这表明了新模型的正确性。（6）对超深亚微米MOS器件单粒子多位翻转的物理机理进行了研究，发现在小尺寸情况下，由于电荷共享所导致的单粒子多位翻转数量与比重都有所上升，建立了基于器件临界电荷Qc r以及收集电荷Qc o的超深亚微米MOS器件单粒子多位翻转表征模型，并通过模拟对该模型进行了验证。模拟结果表明，单个入射粒子所引起的多位翻转情况受到粒子入射的线性能量传输（Linear Transfer Energy）值、入射位置以及入射角度的影响。更多还原

【Abstract】 The electronic devices working in space suffers from radiation effects of spaceparticles, which leads to attenuation of their performance and life time due to thedegeneration of materials of devices after radiation. When degeneration accumulates toa certain extent, it results in device failure ultimately. With the development ofsemiconductor technology, it has been found that failure probability of devices increasesbecause of the decrease of key parameters caused by devices becoming smaller andsmaller. Additionally, size reduction can generate some new effects that influencereliability of the devices indirectly. Therefore, it is necessary to explore a sensitivecharacterization for radiation degeneration and new effects in order to assess reliabilityof the devices.In this paper, the physical mechanism of radiation degeneration in electronicdevices, especially in MOS and bipolar devices, has been researched. Based on theresearch, a method of sensitive characterization about radiation damage has beendeveloped. Moreover, the new single event effect in ultra-deep sub-micron devices hasbeen researched, which mainly focuses on charge sharing, multiple bits upset as well ascorrection of the original charge collection model. The main innovations andcontributions of this paper are the following:(1) The parameter degeneration by radiation in bipolar devices has been analyzed.According to its physical mechanism, a model of noise characterization has been builtand verified. In the experiments, the change rate of noise parameters would reach2500%if the change rate of electrical parameters was approximate3%, which indicatesthat noise parameters are more sensitive than electrical parameters. Thus, noiseparameters can be used as sensitive characterization of radiation damage for bipolardevices.(2) A research on ionization radiation effect and displacement radiation effect inbipolar devices is given. The research indicates that the degeneration mechanismsgenerated by these two radiation effects are not identical. Consequently, they were differentiated through experiments. As a result, the reverse current of a p-n junctiondiode could characterize ionization radiation effect, while the voltage of a p-n junctiondiode could characterize displacement radiation effect efficiently. The model andexperimental results illustrate that the ionization radiation effect is dominated in thecase of low radiation dose. However, the displacement radiation effect becomes moresignificant when radiation dose increases.(3) A research on physical mechanism of radiation degeneration in MOS devices iscarried out. According to the research, a radiation degeneration model and a noisecharacterization model have been constructed and validated separately. The resultsindicate that the increasing number of oxide-trapped charge and interface-trappedcharge produce a saturation phenomenon at different radiation doses and the saturationphenomenon of interface-trapped charge appears at lower dose. Besides, noiseparameters are more sensitive than electrical parameters. Therefore, noise parameterscan be used as sensitive characterization of radiation degeneration for MOS devices.(4) The1/f noise properties of pre-radiation in MOS devices have been analyzed,which demonstrates1/f noise pre-radiation is able to characterize the latent defect inMOS devices efficiently. Based on this analysis, a model for latent defect of MOSdevices has been built and verified. The results show that the pre-radiation1/f noisepower spectral amplitude is direct proportional to post-radiation threshold voltage drift.Therefore, this model is effective to characterize the quantity and severity of latentdefect in MOS devices by using1/f noise parameters.(5) The new effect of a single particle in ultra-deep sub-micron MOS devices hasbeen analyzed. Meanwhile, a new mechanism named charge sharing and a new effectnamed multiple bits upset have been discovered. Then a new model has been set upsince the previous charge collection model cannot be used for ultra-deep sub-microndevices. Using the new model, a simulation was implemented on90nm MOS devicesin order to test the charge collection, and it was verified by Technology Computer AidedDesign(TCAD). As a result, compared with the previous model, new model had moreaccuracy results that was consistent with TCAD simulation results. (6) The physical mechanism of multiple bits upset of a single particle in ultra-deepsub-micron MOS devices has been researched. It indicates that quantity and proportionof multiple bits upset will increase because of charge sharing and scale shrinking ofdevices. In the simulation, a characterization model was established based on criticalcharge Qcrand collecting charge Qco. It turns out that multiple bits upset is affected byLinear Transfer Energy(LTE), location of incidence as well as angle of incidence.更多还原