scholarly journals Analysis of Threshold Voltage Shift for Full VGS/VDS/Oxygen-Content Span under Positive Bias Stress in Bottom-Gate Amorphous InGaZnO Thin-Film Transistors

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 327
Author(s):  
Je-Hyuk Kim ◽  
Jun Tae Jang ◽  
Jong-Ho Bae ◽  
Sung-Jin Choi ◽  
Dong Myong Kim ◽  
...  
Keyword(s):  
Thin Film ◽  
Electric Field ◽  
Oxygen Content ◽  
Threshold Voltage ◽  
Thin Film Transistors ◽  
Electron Trapping ◽  
Threshold Voltage Shift ◽  
Voltage Shift ◽  
Drain Side ◽  
Bottom Gate

In this study, we analyzed the threshold voltage shift characteristics of bottom-gate amorphous indium-gallium-zinc-oxide (IGZO) thin-film transistors (TFTs) under a wide range of positive stress voltages. We investigated four mechanisms: electron trapping at the gate insulator layer by a vertical electric field, electron trapping at the drain-side GI layer by hot-carrier injection, hole trapping at the source-side etch-stop layer by impact ionization, and donor-like state creation in the drain-side IGZO layer by a lateral electric field. To accurately analyze each mechanism, the local threshold voltages of the source and drain sides were measured by forward and reverse read-out. By using contour maps of the threshold voltage shift, we investigated which mechanism was dominant in various gate and drain stress voltage pairs. In addition, we investigated the effect of the oxygen content of the IGZO layer on the positive stress-induced threshold voltage shift. For oxygen-rich devices and oxygen-poor devices, the threshold voltage shift as well as the change in the density of states were analyzed.

Threshold voltage shift under electrical stress in amorphous, polymorphous, and microcrystalline silicon bottom gate thin-film transistors

2009 ◽  
Vol 207 (5) ◽  
pp. 1245-1248 ◽  
Author(s):  
Maher Oudwan ◽  
Oumkelthoum Moustapha ◽  
Alexey Abramov ◽  
Dmitriy Daineka ◽  
Yvan Bonnassieux ◽  
...  
Keyword(s):  
Thin Film ◽  
Threshold Voltage ◽  
Thin Film Transistors ◽  
Microcrystalline Silicon ◽  
Threshold Voltage Shift ◽  
Voltage Shift ◽  
Electrical Stress ◽  
Bottom Gate

scholarly journals Negative threshold voltage shift in an a-IGZO thin film transistor under X-ray irradiation

RSC Advances ◽  
2019 ◽  
Vol 9 (36) ◽  
pp. 20865-20870 ◽  
Author(s):  
Dong-Gyu Kim ◽  
Jong-Un Kim ◽  
Jun-Sun Lee ◽  
Kwon-Shik Park ◽  
Youn-Gyoung Chang ◽  
...  
Keyword(s):  
Thin Film ◽  
Threshold Voltage ◽  
Thin Film Transistor ◽  
Threshold Voltage Shift ◽  
Voltage Shift ◽  
Hydrogen Incorporation ◽  
X Ray ◽  
Spectroscopic Analyses ◽  
Bottom Gate ◽  
Igzo Tft

We studied the effect of X-ray irradiation on the negative threshold voltage shift of bottom-gate a-IGZO TFT. Based on spectroscopic analyses, we found that this behavior was caused by hydrogen incorporation and oxygen vacancy ionization.

scholarly journals Effect of Oxygen Content on Current Stress-Induced Instability in Bottom-Gate Amorphous InGaZnO Thin-Film Transistors

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3149 ◽  
Author(s):  
Sungju Choi ◽  
Jae-Young Kim ◽  
Hara Kang ◽  
Daehyun Ko ◽  
Jihyun Rhee ◽  
...  
Keyword(s):  
Electric Field ◽  
Oxygen Content ◽  
Thin Film Transistors ◽  
Electron Trapping ◽  
Current Stress ◽  
Bias Stress ◽  
Self Heating ◽  
Effect Of Oxygen ◽  
Amorphous Ingazno ◽  
Bottom Gate

The effect of oxygen content on current-stress-induced instability was investigated in bottom-gate amorphous InGaZnO (a-IGZO) thin-film transistors. The observed positive threshold voltage shift (ΔVT) was dominated by electron trapping in the gate insulator (GI), whereas it was compensated by donor creation in a-IGZO active regions when both current flows and a high lateral electric field were present. Stress-induced ΔVT increased with increasing oxygen content irrespective of the type of stress because oxygen content influenced GI quality, i.e., higher density of GI electron traps, as well as typical direct current (DC) performance like threshold voltage, mobility, and subthreshold swing. It was also found that self-heating became another important mechanism, especially when the vertical electric field and channel current were the same, independent of the oxygen content. The increased ΔVT with oxygen content under positive gate bias stress, positive gate and drain bias stress, and target current stress was consistently explained by considering a combination of the density of GI electron traps, electric field relaxation, and self-heating-assisted electron trapping.

Investigation on the Electrical Stability of 5,11-Bis(triethylsilylethynyl)anthradithiophene Thin-Film Transistors

2021 ◽  
Vol 21 (3) ◽  
pp. 1754-1760
Author(s):  
Joel Ndikumana ◽  
Jyothi Chintalapalli ◽  
Jin-Hyuk Kwon ◽  
Jin-Hyuk Bae ◽  
Jaehoon Park
Keyword(s):  
Thin Film ◽  
Threshold Voltage ◽  
Thin Film Transistors ◽  
Ambient Air ◽  
Gate Insulator ◽  
Hydroxyl Groups ◽  
Electrical Stability ◽  
Threshold Voltage Shift ◽  
Voltage Shift ◽  
Domain Boundaries

We investigate the effects of environmental conditions on the electrical stability of spin-coated 5,11-bis(triethylsilylethynyl)anthradithiophene (TES-ADT) thin-film transistors (TFTs) in which crosslinked poly(4-vinylphenol-co-methyl methacrylate) (PVP-co-PMMA) was utilized as a gate insulator layer. Atomic force microscopy observations show molecular terraces with domain boundaries in the spin-coated TEST-ADT semiconductor film. The TFT performance was observed to be superior in the ambient air condition. Under negative gate-bias stress, the TES-ADT TFTs showed a positive threshold voltage shift in ambient air and a negative threshold voltage shift under vacuum. These results are explained through a chemical reaction between water molecules in air and unsubstituted hydroxyl groups in the cross-linked PVP-co-PMMA as well as a charge-trapping phenomenon at the domain boundaries in the spin-coated TES-ADT semiconductor.

Threshold Voltage Shift of Amorphous Silicon Thin-Film Transistors During Pulse Operation

1991 ◽  
Vol 30 (Part 1, No. 12B) ◽  
pp. 3719-3723 ◽  
Author(s):  
Ryoji Oritsuki ◽  
Toshikazu Horii ◽  
Akira Sasano ◽  
Ken Tsutsui ◽  
Toshiko Koizumi ◽  
...  
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Threshold Voltage ◽  
Thin Film Transistors ◽  
Silicon Thin Film ◽  
Pulse Operation ◽  
Threshold Voltage Shift ◽  
Voltage Shift
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