非晶铟镓锌氧化物薄膜晶体管在光照及电应力下的退化研究

发布时间：2018-04-04 01:40

本文选题：铟镓锌氧化物　切入点：薄膜晶体管　出处：《苏州大学》2015年硕士论文

【摘要】：本文主要提出了一个统一的退化模型来解释非晶铟镓锌氧化物(a-IGZO)薄膜晶体管在不同光照及电应力下的退化行为。在提出的统一退化模型中,光激发的双离化氧空位(Vo2+)缺陷及其在电场中的传输机制是引起器件阈值电压(Vth)漂移的两个关键因素。同时,光激发的Vo2+周围会有附加的缺陷态产生,从而影响器件的亚阈值特性。随后,我们做了一系列a-IGZO TFT器件在蓝光光照及电应力下的可靠性实验,包括:单独电应力,单独光照,正偏光照(PBIS),负偏光照(NBIS)。器件的退化现象在不同的应力下各不相同。正栅压应力(PBS)下,器件的转移曲线有个正向的平移;负栅压应力(NBS)下,器件不退化;单独光照下,器件的转移曲线负向漂移,并伴有亚阈值区域的退化;PBIS情况下,转移曲线正向移漂,并伴有亚阈值区域的退化;NBIS情况下,转移曲线负向移漂,亚阈值区域有严重的退化。虽然不同应力下退化现象不同,但是都能用我们提出的统一模型作很好的解释。此外,我们还研究了a-IGZO TFT器件在不同波长光照及不同光强下的退化。除了蓝光,我们还研究了红光,绿光光照下器件的可靠性。在做蓝光NBIS的时候我们调整了蓝光的光强,研究光强对器件的影响。我们发现,是曝光量而不是应力时间或光强对器件在NBIS情况下起主要作用。
[Abstract]:In this paper, a unified degradation model is proposed to explain the degradation behavior of amorphous indium gallium zinc oxide oxide a-IGZO thin film transistors under different illumination and electrical stresses.In the proposed unified degenerative model, the photoexcited double ionization oxygen vacancy Vo2) defect and its transmission mechanism in the electric field are the two key factors that cause the threshold voltage shift of the device.At the same time, there will be additional defect states around the photoexcited Vo2, which will affect the subthreshold characteristics of the device.Subsequently, a series of reliability experiments of a-IGZO TFT devices under blue light and electrical stress have been done, including: single electric stress, single light, positive bias light, negative bias light.The degradation of devices varies under different stresses.Under the positive gate stress (PBS), the transfer curve of the device has a positive translation, the device does not degenerate under the negative gate voltage stress (NBS), the transfer curve of the device drifts negatively under individual illumination, and it is accompanied by the degradation of the sub-threshold region (PBIS).In the case of the positive drift of the transfer curve with the degradation of the sub-threshold region, the negative drift of the transfer curve and the serious degradation of the sub-threshold region are observed.Although the degradation phenomenon is different under different stresses, it can be well explained by the unified model proposed by us.In addition, we also study the degradation of a-IGZO TFT devices under different wavelength illumination and different light intensity.In addition to blue light, we also study the reliability of devices under red and green light.We adjust the light intensity of blue light to study the influence of light intensity on the device.We find that it is exposure rather than stress time or intensity that plays a major role in the NBIS case.
【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN321.5

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