Improvement in the bias stability of tin oxide thin-film transistors by hafnium doping

Kim, Woong-Sun; Moon, Yeon-Keon; Kim, Kyung‐Taek; Shin, Sae-Young; Park, Jong-Wan

doi:10.1016/j.tsf.2011.08.028

Cited by 17 publications

(6 citation statements)

References 21 publications

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“…Thin film transistors based on amorphous oxide films (OxTFTs) have attracted tremendous interest as TFT backplanes in active-matrix organic light emitting diodes (OLEDs) and liquid crystal displays owing to their high mobilities. [1][2][3][4][5][6][7] Intensive developments on oxide compounds including InO x -based, [8][9][10][11][12][13] ZnO x -based, 14 SnO x -based 15 and mixed channel materials such as InZnO x -based OxTFTs [16][17][18][19][20][21][22][23][24][25] have been widely studied in OxTFTs in recent decades because of their excellent electrical stabilities and high mobilities. Among them, InGaZnO (IGZO) 1,2,26 and InSnZnO (ITZO) 18,19 are currently being developed for use as commercial TFT backplanes because of their superior properties and high electron mobilities.…”

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confidence: 99%

Reduction of the interfacial trap density of indium-oxide thin film transistors by incorporation of hafnium and annealing process

et al. 2015

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The stable operation of transistors under a positive bias stress (PBS) is achieved using Hf incorporated into InOx-based thin films processed at relatively low temperatures (150 to 250 °C). The mobilities of the Hf-InOx thin-film transistors (TFTs) are higher than 8 cm2/Vs. The TFTs not only have negligible degradation in the mobility and a small shift in the threshold voltage under PBS for 60 h, but they are also thermally stable at 85 °C in air, without the need for a passivation layer. The Hf-InOx TFT can be stable even annealed at 150 °C for positive bias temperature stability (PBTS). A higher stability is achieved by annealing the TFTs at 250 °C, originating from a reduction in the trap density at the Hf-InOx/gate insulator interface. The knowledge obtained here will aid in the realization of stable TFTs processed at low temperatures.

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confidence: 99%

Reduction of the interfacial trap density of indium-oxide thin film transistors by incorporation of hafnium and annealing process

et al. 2015

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“…These problems can be resolved by doping with suitable cations acting as carrier repressors and crystallization stoppers because tin oxide is a bipolar OS, in which both n‐ or p‐type carrier doping are possible in the same SnO x material. To date, several doping elements have been reported to improve the performance of tin‐oxide‐based TFTs, such as aluminum, zirconium, hafnium, and fluorine . Furthermore, lower valence cations, such as nitrogen (N), indium, and antimony (Sb), have been suggested to be good p‐type dopants in SnO 2 .…”

Section: Introductionmentioning

confidence: 99%

Effects of Oxygen Ratio on the Properties of Tin Oxide Thin Films Doped with Bismuth

Bang

Seo

Bae

et al. 2019

Physica Status Solidi (a)

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This study examins the effects of the oxygen ratio on the properties of bismuth (Bi)‐doped tin oxide (Bi‐SnOx) films deposited by radio frequency magnetron sputtering using a SnO (90 at%)‐Bi (10 at%) ceramic target. The properties of the samples are characterized by X‐ray photoelectron spectroscopy (XPS), Hall effect measurements, dynamic‐secondary ion mass spectrometry (D‐SIMS), and X‐ray diffraction (XRD). The samples deposited without oxygen gas exhibit Sn4+ and Sn2+ XPS peak areas of 44.7 and 41.1%, respectively. The Sn4+ area increases to 64.1% with increasing oxygen ratio up to 20% with a concomitant decrease of the Sn2+ area to 26%, indicating that SnO2 with n‐type conductivity is the dominant phase under a higher oxygen partial pressure. XPS shows that with increasing oxygen ratio, the chemical state of Bi changes from metallic Bi (Bi0) to Bi3+. Furthermore, with increasing oxygen ratio, the Bi content in the samples increases because of the increase in Bi2O3 formation, which causes a decrease in the number of oxygen vacancies in the samples. These results suggest that the oxygen ratio is useful for controlling Bi doping in SnOx films. Therefore, Bi doping is valuable for suppressing the formation of oxygen vacancies and improving the properties of SnOx films.

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“…Up to now, the researches related to tin oxide TFTs are relatively under‐researched compared with the InO x ‐ and ZnO‐based TFTs. One reason is that the intrinsic tin oxide semiconductor is polycrystalline, and most TFTs using SnO x semiconductors as channel layer have relatively high carrier concentration, which leads to impractically high operation gate voltage . Several doping elements, such as Al , Zr have been investigated as the carrier suppressors in SnO 2 ‐based TFTs, but the general performances have not reach the requirement of practical devices.…”

Section: Introductionmentioning

confidence: 99%

Effects of silicon doping on the performance of tin oxide thin film transistors

Yang

Zhao

Tao

et al. 2015

Phys. Status Solidi A

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Thin film transistors (TFTs) with silicon‐doped tin oxide (TSO) as channel layer were prepared by radio frequency magnetron sputtering. The decreased defect‐state‐related peak in photoluminescence (PL) excitation spectra and oxygen‐vacancy‐related O 1s peak in X‐ray photoelectron spectroscopy (XPS) with increasing Si content, accompanied by the decreased off‐state current and positive shift of turn‐on voltage, confirms that silicon can be a good carrier suppressor. The optimum TFT performance after annealing at 300 °C was achieved at Si content 5.4 at.%, with saturation mobility of 5.3 cm2 V−1 s−1, turn‐on voltage of −0.2 V, and on‐off current ratio of 3.3 × 106, respectively. Increasing the annealing temperature is useful to improve the mobility, but the polycrystalline structure formed above 350 °C goes against the uniformity of oxide TFTs.

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Improvement in the bias stability of tin oxide thin-film transistors by hafnium doping

Cited by 17 publications

References 21 publications

Reduction of the interfacial trap density of indium-oxide thin film transistors by incorporation of hafnium and annealing process

Reduction of the interfacial trap density of indium-oxide thin film transistors by incorporation of hafnium and annealing process

Effects of Oxygen Ratio on the Properties of Tin Oxide Thin Films Doped with Bismuth

Effects of silicon doping on the performance of tin oxide thin film transistors

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