不同宽长比的柔性LTPS TFT的电应力可靠性  

Electrical Stress Reliability of Flexible LTPS TFT with Different Width-Length Ratios

作　　者：张之壤 朱慧 刘行 张轶群 徐朝 郑文轩 Zhang Zhirang;Zhu Hui;Liu Xing;Zhang Yiqun;Xu Chao;Zheng Wenxuan(Novel Semiconductor Devices and Reliability Laboratory,Faculty of Information Technology,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学信息学部新型半导体器件与可靠性实验室,北京100124

出　　处：《半导体技术》2024年第6期589-595,共7页Semiconductor Technology

基　　金：国家自然科学基金(62374012)。

摘　　要：为了研究不同宽长比的柔性低温多晶硅薄膜晶体管(LTPS TFT)的电应力可靠性,测试了器件的I-V特性,以表征器件在强电场直流应力下由于自热效应和热载流子效应带来的电学性能退化。通过瞬态电流法表征了器件在强电场直流应力下的时间常数谱,并对其产生的新陷阱进行定位,分析了产生陷阱的内在机理。结果表明,在相同的强电场直流应力下宽长比为3/2.5的器件,其电学参数变化最大,自热效应以及热载流子效应带来的影响也最大。自热效应导致器件性能退化的主要原因是较大的栅源电压导致Si/SiO2界面处和栅氧化层中的陷阱增多,而热载流子效应导致器件性能退化的主要原因则是由于较大的漏源电压使得漏极晶界陷阱态密度急剧升高。In order to research the electrical stress reliability of flexible low-temperature polysilicon thin film transistors(LTPS TFTs)with different width-length ratios,the I-V characteristics of the device were tested to characterize the electrical performance degradation caused by self-heating effect and hot carrier effect under strong electric field DC stress.The time constant spectra of the device under strong electric field DC stress were characterized by transient current method,the new traps generated in the device were located,and the internal mechanism of the traps were analyzed.The results show that under the same strong electric field DC stress,the device with the width-length ratio of 3/2.5 exhibits the greatest changes in electrical parameters,and the influences of self-heating effect and hot carrier effect are also the greatest.The main reason for the performance degradation of the device caused by the self-heating effect is that the larger gate-source voltage leads to the increase of traps at the Si/SiO_2 interface and in the gate oxide layer,while the main reason for the performance degradation of the device caused by the hot carrier effect is that the larger drain-source voltage causes the sharp increase of traps state density at the drain grain boundary.

关 键 词：柔性低温多晶硅薄膜晶体管(LTPS TFT) 自热效应 热载流子效应 瞬态电流 强电场直流应力 

分 类 号：TN321.5[电子电信—物理电子学] TN306