The influence of visible light on transparent zinc tin oxide thin film transistors

Görrn, Patrick; Lehnhardt, Marcus; Riedl, Thomas; Kowalsky, Wolfgang

doi:10.1063/1.2806934

Cited by 154 publications

(110 citation statements)

References 16 publications

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“…12 The trapped charges enhance the TFT conductance and remain for a long period of time leading to a persistent photoconductivity (PPC). G€ orrn et al 13 and Gosain et al…”

mentioning

confidence: 99%

Improving positive and negative bias illumination stress stability in parylene passivated IGZO transistors

Kiazadeh

Gomes

Barquinha

et al. 2016

Applied Physics Letters

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The impact of a parylene top-coating layer on the illumination and bias stress instabilities of indium-gallium-zinc oxide thin-film transistors (TFTs) is presented and discussed. The parylene coating substantially reduces the threshold voltage shift caused by continuous application of a gate bias and light exposure. The operational stability improves by 75%, and the light induced instability is reduced by 35%. The operational stability is quantified by fitting the threshold voltage shift with a stretched exponential model. Storage time as long as 7 months does not cause any measurable degradation on the electrical performance. It is proposed that parylene plays not only the role of an encapsulation layer but also of a defect passivation on the top semiconductor surface. It is also reported that depletion-mode TFTs are less sensitive to light induced instabilities. This is attributed to a defect neutralization process in the presence of free electrons.

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“…12 The trapped charges enhance the TFT conductance and remain for a long period of time leading to a persistent photoconductivity (PPC). G€ orrn et al 13 and Gosain et al…”

mentioning

confidence: 99%

Improving positive and negative bias illumination stress stability in parylene passivated IGZO transistors

Kiazadeh

Gomes

Barquinha

et al. 2016

Applied Physics Letters

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“…In the ionization oxygen vacancy (V O ) model for the LS insta- photo-generated electrons increase the conductivity in the channel [7][8][9]. The enhanced conductivity is known to be persistent because the state transforming from V O 2+ to V O 0 requires a large amount of energy to change the electron configuration.…”

Section: Resultsmentioning

confidence: 99%

“…Although a-IGZO TFTs have such desirable properties, the instability of their threshold voltage (V TH ) under illumination with light can be a critical obstacle for their use in displays because the devices are exposed to ambient light during operation. Recently, several studies have reported on the V TH instability under a negative bias and under illumination stress (NBIS), and the results can be summarized into three models where the degradation is caused by (1) light-induced oxygen interstitial generation [4]; (2) trapping of a photo-generated hole [5,6]; and (3) an ionization oxygen vacancy [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

A Light-induced Threshold Voltage Instability Based on a Negative-U Center in a-IGZO TFTs with Different Oxygen Flow Rates

Kim¹,

Kim²,

Jeong³

et al. 2014

Transactions on Electrical and Electronic Materials

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In this paper, we investigate visible light stress instability in radio frequency (RF) sputtered a-IGZO thin film transistors (TFTs). The oxygen flow rate differs during deposition to control the concentration of oxygen vacancies, which is confirmed via RT PL. A negative shift is observed in the threshold voltage (V TH ) under illumination with/without the gate bias, and the amount of shift in V TH is proportional to the concentration of oxygen vacancies. This can be explained to be consistent with the ionization oxygen vacancy model where the instability in V TH under illumination is caused by the increase in the channel conductivity by electrons that are photo-generated from oxygen vacancies, and it is maintained after the illumination is removed due to the negative-U center properties.

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“…The zinc tin oxide (ZTO) film was thought to be an effective active layer for TTFTs because of its wide energy band gap and high resistivity [12][13][14]. We have reported that ZTO TTFTs employing In as source/drain electrodes exhibit a mobility greater than 18.0 cm 2 /Vs [15].…”

Section: Introductionmentioning

confidence: 98%

Effects of an Aluminum Contact on the Carrier Mobility and Threshold Voltage of Zinc Tin Oxide Transparent Thin Film Transistors

Ma¹

2014

Journal of Electrical Engineering and Technology

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-We fabricated amorphous zinc tin oxide (ZTO) transparent thin-film transistors (TTFTs).The effects of Al electrode on the mobility and threshold voltage of the ZTO TTFTs were investigated. It was found that the aluminum (Al)-ZTO contact decreased the mobility and increased the threshold voltage. Traps, originating from AlO x , were assumed to be the cause of degradation. An indium tin oxide film was inserted between Al and ZTO as a buffer layer, forming an ohmic contact, which was revealed to improve the performance of ZTO TTFTs.

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The influence of visible light on transparent zinc tin oxide thin film transistors

Cited by 154 publications

References 16 publications

Improving positive and negative bias illumination stress stability in parylene passivated IGZO transistors

Improving positive and negative bias illumination stress stability in parylene passivated IGZO transistors

A Light-induced Threshold Voltage Instability Based on a Negative-U Center in a-IGZO TFTs with Different Oxygen Flow Rates

Effects of an Aluminum Contact on the Carrier Mobility and Threshold Voltage of Zinc Tin Oxide Transparent Thin Film Transistors

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