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基于光激电流法研究聚酰亚胺薄膜陷阱能谱
Study on Deep Trap Spectrum in Polyimide Based on Photo-Stimulated Discharge
【作者】 曹景磊；
【导师】 陈春天；
【作者基本信息】 哈尔滨理工大学 ， 凝聚态物理， 2011， 硕士
【摘要】 作为综合性能非常优异的聚合物材料,聚酰亚胺在航空航天、微电子技术等高技术领域得到广泛的应用。长期工作在电应力的作用下,空间电荷行为对绝缘材料的老化和击穿特性带来巨大的影响,而陷阱的性质决定着电荷的存贮和输运。因此,研究聚合物材料的陷阱结构和分布对提高其性能有重要的意义。光激电流(PSD)法是研究聚合物材料中陷阱结构及空间电荷存贮和输运的有效工具,能实现无损、等温测量,可以用来研究能级较深的电荷陷阱。本文较详细的介绍了实验系统,并对实验系统的可行性及可靠性进行了验证,结果表明此系统完全可以达到实验要求。利用该装置测量了未注入、不同注入时间和不同注入电压条件下的普通聚酰亚胺薄膜和纳米杂化聚酰亚胺薄膜的光激电流谱,并对注入电荷后的样品进行多次扫描。通过对实验结果的分析发现,两种型号的PI薄膜的陷阱能级分布为带状,分别为3.1eV-4.2eV和3.1eV-4.3eV;增加注入时间,光激电流随之增大,注入时间由60min增加到90min,电流峰向短波方向移动,表明注入到陷阱内的电荷首先被较浅的陷阱俘获,在电场的作用下,注入电荷或部分已被浅陷阱俘获的电荷向相对深陷阱能级移动;增大注入电压,光激电流值随之增大。同时,对聚酰亚胺的老化和击穿机制进行分析,发现破坏发生在空间电荷脱陷过程中。
【Abstract】 In varied polymers, the comprehensive performance of polyimide is better than others, and it has been widely used in high-tech fields, as aerospace, microelectronics technology, et al. Aging and breakdown can occur in polyimide under long-term electric stressing due to space charge behavior. Charge storage and transport is decided by trap characteristics, so it is significant for improving polymer material properties through researching structure and distribution of trap.Photo-stimulated discharge (PSD) is an effective tool to study structure of trap, the storage and transport of charge in polymer. It is an isothermal measurement process. The PSD measurement is no damage. Deep trsps can be researched by this method. The paper described experimental system detailedly, verified stability and reliadility. The results showed that the measurement device meet experimental requirements well.PSDs in PI-100HN and PI-100CR film were tested under no charged, different injection time and different injection voltage, and multiple scans. The measurement results were shown that the distribution of trap levels in two types film is banded, 3.1eV-4.2eV for PI-100HN, 3.1eV-4.3eV for PI-100CR; the current increased when the injection time increased, peaks moved to the shortwave when injection time was increased from 60min to 90min, it showed that the injection charge was captured by shallow trap, and then some of trapped charge moved to the relative deeper trap with new injection charge under electric field; the current increased when the injection voltage increased. In addition, the aging and breakdown mechanisms in PI were analysed, it was found out that the broken was occurred in detrapping process.