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肖特基二极管抗辐照能力表征技术研究
Research on the Characterization Technique for Irradiation-proof Competence of Schottky Barrier Diode
【作者】 杨丽侠;
【导师】 杜磊;
【作者基本信息】 西安电子科技大学 , 材料科学与工程, 2008, 硕士
【摘要】 为了满足航天电子系统对SBD抗辐照能力进行评估的要求,本论文课题通过理论研究和60Coγ射线辐照实验数据分析,研究了器件辐照损伤效应及其抗辐照能力的表征方法。文中设计了SBD器件60Coγ射线辐照实验,测试器件电特性和1/f噪声特性,详细分析器件损伤微观机制,深入研究辐照损伤对SBD器件正反向I-V特性和1/f噪声的影响,并确定反向漏电流、击穿电压和1/f噪声功率谱强度拟合参数B为器件抗辐照能力表征参量。研究结果表明,辐照主要产生电离效应,在器件表面的钝化层中引人界面态,使器件性能退化,反向击穿电压减小、漏电流变大、1/f噪声参数B急剧增加;但是没有明显引起正向特性变化。辐照诱生新的界面态,改变界面态密度分布,进而调制了肖特基势垒高度,增大表面复合速度,是引起器件性能退化主要原因,也是1/f噪声剧烈增加的主要原因。基于SBD辐照损伤机理及1/f噪声的总剂量效应、产生机制及1/f噪声的迁移率涨落和载流子数涨落模型的研究,建立SBD器件1/f噪声抗辐照能力表征模型。提出基于1/f噪声的SBD器件抗辐照能力表征技术,并依据SBD器件抗辐照能力表征参量及国军标,实现器件无损筛选。依据实验结果验证,参数B越大,偏离标准值越多,器件可靠性越差,抗辐照能力越低,在辐照环境下工作越容易失效。
【Abstract】 To meet the demand of spaceflight electronic system for measurement of SBD radiation-proof competence, a research is performed in this paper on SBD’s radiation damage effect and the relevant characterization technique of radiation-proof competence, by means of theoretical research and experiment data analyses in a 60Coγ-ray radiation experiment. A 60Coγ-ray radiation experiment is undertaken, in which both the electrical characteristics and the 1/f noise characteristics of the device under test are measured so as to launch a detailed analysis into the micro-scope damage mechanism of the device and perform a in-depth research into the effect of radiation caused damage on SBD’s positive and reverse I-V characteristics, as well as its 1/f noise characteristics, and choosing the leakage current, breakdown voltage, and the fitting parameter B of 1/f noise power spectrum intensity to characterize SBD’s radiation-proof competence.It’s showed that: the ionizing effect caused by radiation, which involves the rising of interface states in the passivation layer of the device’s surface, could lead to the degradation of the device, the decrease of the reverse breakdown Voltage, the increase of the drain current, as well as the significant increase of the 1/f noise level, however, little changes is caused to the positive electrical characteristics. The radiation induced interface states which change the distribution of interface state density, and moreover modulate the Schottky barrier height and increase the velocity of recombination in surface, lead to the degradation of device performance as well as the significant increasing of 1/f noise level.Based on the research of the mechanism of radiation damage and total dose effect and the generating mechanism on Schottky barrier diodes(SBD) , and model of the mechanisms of carrier mobility fluctuation and carrier number fluctuation of 1/f noise, the effect of radiation damage on 1/f noise of SBD was studied in this paper. Then, a 1/f noise based characterization technique for SBD’s radiation-proof competence is proposed in this paper, by which the device’s non-destruction screening could be realized through the character parameter and National Standards of Device Quality for Military Utility. The experiment result validated that: the higher noise level and the larger deviation from the standard value do indicate the worse reliability and poorer radiation-proof competence, which implies a higher probability of failure for the device to work in irradiation environment.
【Key words】 Schottky Barrier Diode; 60CoγRadiation; Ionization Effect; 1/f noise; Interface State;