Quantitative Analysis of the Effect of Hydrogen Diffusion from Silicon Oxide Etch-Stopper Layer into Amorphous In-Ga-Zn-O on Thin-Film Transistor
Quantitative Analysis of the Effect of Hydrogen Diffusion from Silicon Oxide Etch-Stopper Layer into Amorphous In-Ga-Zn-O on Thin-Film Transistor
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DOI：
10.1109/ted.2014.2359739
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发表时间：
2014-11-01
影响因子：
3.1
通讯作者：
Furuta, Mamoru
中科院分区：
文献类型：
--
作者：
Toda, Tatsuya;Wang, Deapeng;Furuta, Mamoru
为了研究氢从氧化硅蚀刻阻止层（SiOx ES）扩散到非晶In-Ga-Zn-O（a-IGZO）中对薄膜晶体管（TFT）性能和稳定性的影响，我们制造了具有SiOx ES层的a-IGZO TFT通过等离子体增强化学气相沉积在各种硅烷（SiH 4）分压（P[SiH 4]）下沉积。然后，进行定量分析以研究a-IGZO的氢含量与TFT的电性能和稳定性之间的关系。我们发现，当在较高的P[SiH 4]下沉积SiOx ES层时，在TFT的背沟道处形成低电阻区域，导致急剧的负阈值电压（V-th）偏移。此外，还发现在前沟道处，a-IGZO的载流子浓度的增加与a-IGZO中的氢量的增加成比例。另一方面，当P[SiH 4]增加时，TFT的亚阈值摆幅、滞后和栅极偏置稳定性得到改善。结果表明，从SiOxES层扩散的氢钝化了a-IGZO和/或栅绝缘层/a-IGZO界面的电子陷阱，而且几乎所有的氢都是a-IGZO中的浅施主。
To investigate the effect of hydrogen diffusion from the silicon oxide etch-stopper (SiOx ES) layer into the amorphous In-Ga-Zn-O (a-IGZO) on thin-film transistor (TFT) properties and stabilities, we fabricated a-IGZO TFTs with a SiOx ES layer deposited by plasma-enhanced chemical vapor deposition at various silane (SiH4) partial pressures (P[SiH4]). Then, quantitative analysis was performed to investigate the relationship between the hydrogen content of the a-IGZO and electrical properties and stability of the TFTs. We found that a low resistance region was formed at the backchannel of the TFT, when the SiOx ES layer was deposited at higher P[SiH4], leading to a drastic negative threshold voltage (V-th) shift. In addition, it was also found that at the frontchannel, the increase in the carrier concentration of a-IGZO was proportional to the increase in the amount of hydrogen in a-IGZO. On the other hand, when P[SiH4] was increased, the subthreshold swing, hysteresis, and gate-bias stability of the TFT improved. The results indicate that hydrogen diffused from the SiOx ES layer passivates the electron traps at the a-IGZO and/or gate insulator/a-IGZO interface, and almost all of the hydrogen also acts as shallow-donor in a-IGZO.