【作者】 韩光；

【导师】 庄奕琪；

【作者基本信息】 西安电子科技大学 ， 微电子学与固体电子学， 2010， 硕士

【摘要】 双极电路广泛应用于航天、核反应堆等具有辐射性的领域。研究表明,辐射后双极器件参数退化是该类电路稳定性降低的主要因素之一,因此迫切需要对双极晶体管辐射损伤效应进行深入研究,并提出一种表征方法来评价双极晶体管的抗辐射能力。随着对电子元器件低频噪声的深入研究,人们发现低频噪声能更敏感的反映出半导体器件的内部缺陷。理论研究表明,双极晶体管经辐照引起的内部缺陷所导致低频噪声的相对变化量要远远大于其增益的相对变化量。因此本文利用1/f噪声作为分析工具,通过测量双极晶体管的1/f噪声,对器件的质量、可靠性和抗辐照能力进行评估和表征。本文首先在研究双极晶体管工作原理和辐射应用环境的基础上,深入分析了双极晶体管辐射损伤的失效模式及失效机理。其次,研究双极晶体管低频噪声测试方法,建立测试低频噪声电路。大量的噪声测试结果(白噪声、1/f噪声和g-r噪声)表明,该测试电路能准确测试并分析双极晶体管低频噪声及其表征参数。第三,基于上述理论研究和测试系统,完成了双极晶体管多次剂量(30krad、90krad、210krad、450krad)辐射试验及其试验结果对比分析,辐射前后器件的常规电参数(电流增益)和低频噪声参数(1/f噪声幅度B,频率指数γ和转折频率fc)的变化趋势表明:随着辐射剂量的增加,双极晶体管的电流增益不断减小,1/f噪声不断增加。第四,基于上述实验结果和理论研究,对比分析了辐照前后电参数和噪声参数的变化规律,优选出了1/f噪声幅值B作为噪声灵敏表征参量,基于双极晶体管1/f噪声模型,引入辐射损伤机制,建立了双极晶体管辐射损伤的噪声表征模型。最后,以辐射损伤噪声表征模型为基础,初步提出了基于敏感参量的双极晶体管抗辐射能力表征方法。更多还原

【Abstract】 Bipolar circuits are widely used in aerospace, nuclear reactor and other radioactive occasions. I was revealed that the degradation in performance of these bipolar circuits after ionizing radiation is one of the important causes that lead to degradation in reliability or even to failure of these circuits. Therefore, a study of radiation effects on bipolar transistors performance and an effective characterization technique for the evaluation of the anti-radiation capacity of bipolar devices are required urgently. With the advancement in low-frequency noise theory, it was discovered that low-frequency noise pertains a close relation with the microstructures in electronic devics, and therefor can be taken as a sensitive parameter to dignose the quality and reliability of electronic devices. From theoretical studies we know, the relative changes in low-frequency noise parameters are more significant compared with the relative change in the conventional parameters of bipolar transistors, such as current gain, before and after irradiation stress. As a result, 1/f noise was taken as an ideal probing tool to evalute and characterize the quality, reliability and anti-radiation capacity of bipolar transistors in this work.The content of this thesis was organized as follows. First, the failure modes and mechanisms of bipolar transistors under radiation stress were analyzed in datail based on the working principle of bipolar transistors and the characteristics of real radiation application environment. Second, the low-frequency noise testing technique of bipolar transistors was explored and a low-freqnecy noise testing system was built. It was validated by a large amount of measured data that, this system can accurately measure and analyze the low-frequency noise signal and extracte related parameters. Third, based on the above mentioned theoretical knowledge and testing system, both parameters of conventional current gains and low-frequency noise (1/f noise amplitude B, exponent coefficientγand conner frequency) was measured bofore and after several doses of (30krad, 90krad, 210krad, 450krad) radiation experiments. It was found that, the gain of the bipolar transistor decreases with radiation dose, whereas, the low-frequency amplitudes increase. Fourth, the gain of the bipolar transistor and the amplitudes of low-frequency noise were chosen as indicators and compared before and after radiation experiments. A new model of low-frequency noise for the characterization of radiation degradation of bipolar transistors was presented with the help of traditional 1/f noise model of bipolar transistors, and based on which a systematic characterization technique for the anti-radiation capacity was brought forward.更多还原