DocumentCode :
1765887
Title :
Quantitative Analysis of the Effect of Hydrogen Diffusion from Silicon Oxide Etch-Stopper Layer into Amorphous In–Ga–Zn–O on Thin-Film Transistor
Author :
Toda, Takechi ; Deapeng Wang ; Jingxin Jiang ; Mai Phi Hung ; Furuta, Mamoru
Author_Institution :
Grad. Sch. of Eng., Kochi Univ. of Technol., Kami, Japan
Volume :
61
Issue :
11
fYear :
2014
fDate :
Nov. 2014
Firstpage :
3762
Lastpage :
3767
Abstract :
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 (Vth) 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.
Keywords :
amorphous semiconductors; carrier density; electron traps; etching; gallium compounds; indium compounds; passivation; plasma CVD; silicon compounds; thin film transistors; Amorphous Thin-Film Transistor; P[SiH4]; SiOx ES layer; SiOx-InGaZnO; TFT; carrier concentration; electrical property; electron trap; gate-bias stability; hydrogen diffusion effect; low resistance region; passivation; plasma-enhanced chemical vapor deposition; quantitative analysis; shallow-donor; silane partial pressure; silicon oxide etch-stopper layer; Annealing; Hydrogen; Logic gates; Stability analysis; Stress; Thin film transistors; Amorphous In–Ga–Zn–O (a-IGZO); Amorphous In??Ga??Zn??O (a-IGZO); etch-stopper (ES); hydrogen diffusion; silane (SiH₄) partial pressure; silane (SiH4) partial pressure; silicon oxide (SiOx); thin-film transistor (TFT); thin-film transistor (TFT).;
fLanguage :
English
Journal_Title :
Electron Devices, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9383
Type :
jour
DOI :
10.1109/TED.2014.2359739
Filename :
6919276
Link To Document :
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