Enhanced Stability in Zr-Doped ZnO TFTs With Minor Influence on Mobility by Atomic Layer Deposition

Yang, Jun; Zhang, Yongpeng; Qin, Cunping; Ding, Xiaobin; Zhang, Jianhua

doi:10.1109/ted.2019.2896313

Cited by 34 publications

(32 citation statements)

References 34 publications

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“…12.38 10 7 --2019 [23] e) LaInZnO/ b) SiN x 150 2.64 10 9 --2010 [44] a) LaInZnO/ b) SiN x 550 4.2 10 6 1 -2012 [45] a) HfInZnO/ b) SiN x 500 1.94 10 6 --2010 [26] a) ZrInZnO/ a) LaZrO 400 6.23 10 9 -3.5 2013 [27] a) LaZnSnO/ b SiO 2 500 4.2 10 8 --2016 [28] a) LaZnO/ b) ZrO x 350 22.43 10 8 ≈0 0.06 2020 [63] d) ZrZnO/ d) AlO x 150 12.38 10 7 -0.61 2019 [64] a) (ZnO/InO 3 )/ b) SiO 2 200 50 10 5 -3.4 2019 [65] a) ZnO/ b) SiO 2 150 4.5 10 6 22 2018 [66] e) YZnO/ b) SiO 2 150 9.8 10 7 -5.3 2019 [67] d) (ZnO/4MP)/ d) Al 2 O 3 150 30 10 5 -2.3 2020 [68] a)…”

Section: Resultsmentioning

confidence: 99%

“…The device performances such as mobility, on/off current ratio, and SS of previous reports with our results are summarized in Table 1. [1,23,24,[26][27][28]41,[44][45]52,[54][55][56][57][63][64][65][66][67][68] To explain the role of Gd and Li in ZnO, we propose a model shown in Figure 5d-f, where the Zn 2+ ion can be replaced by the Gd 3+ ion, reducing electron concentration in a channel. The Li + replaces the Zn 2+ interstitial site, inducing extra electron in the channel.…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

“…Metal doping in ZnO, such as In, Li, N, F, Al, Ga, Hf, La, Mg, Y, and Zr is proposed to improve the performance and/or stability. [ 16–23 ] Many ternary and quaternary metal oxide TFTs are reported to improve both stability and mobility, but the results are not promising. Adamopoulos et al.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Extremely Stable, High Performance Gd and Li Alloyed ZnO Thin Film Transistor by Spray Pyrolysis

Saha

Bukke

Jang

2020

Adv Elect Materials

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ZnO is a well-known oxide semiconductor because of its excellent electrical and optical properties due to its crystalline structure with high carrier mobility and tunable bandgap by alloying. [13,14] Although, ZnO TFT has high carrier density with crystalline structure, it has some limitations, such as instabilities. It is known that the instability of pristine ZnO is related to the grain boundary defects related to oxygen vacancy and Zn interstitial. [15] Most of pristine ZnO TFTs show negative turn-on voltage owing to its high carrier concentration, which limits the application of the TFTs to gate drivers of active-matrix organic light-emitting diode display. Metal doping in ZnO, such as In, Li, N, F, Al, Ga, Hf, La, Mg, Y, and Zr is proposed to improve the performance and/or stability. [16-23] Many ternary and quaternary metal oxide TFTs are reported to improve both stability and mobility, but the results are not promising. Adamopoulos et al. [24] reported high mobility of ZnO TFT (85 cm 2 V −1 s −1) by Li incorporation on spray pyrolyzed ZrO x gate insulator. The increase in mobility by Li incorporation is due to the increase in grain size, but due to high carrier concentration and defects in semiconductor and interface, the offstate currents are high (10 −8 A). Whereas, Park et al. [25] reported La doping in amorphous IZO TFT which reduces the oxygen deficiency and improves the stability but the mobility is low (≈4.2 cm 2 V −1 s −1). Xifeng et al. [26] reported electron mobility ≈1.94 cm 2 V −1 s −1 by Hf doping in amorphous IZO TFT, where Hf works as carrier suppressor and increases the on/off current ratio by lowering the off-currents. Tue et al. [27] reported the Zr doping in amorphous IZO TFT to control the oxygen vacancies due to its lower slandered electron potential to the off current. Jun et al. [28] reported the La doping in amorphous ZTO TFT to improve the subthreshold swing and on/off current ratio. The electronegativity, ionic radius, and dopant-oxygen bond dissociation energy are important to improve the performance and stability of oxide TFT. As the difference of electronegativity between dopants and oxygen rises, the metaloxygen bond energy increases. Besides, the low standard electrode potential (SEP) of metal ion can decrease the traps due to its binding tendency with oxygen. [29] Higher bond dissociation energy leads to the stronger metal-oxygen network and less oxygen vacancy, which helps to improve the stability of the TFTs. [30] A Gd has lower electronegativity (1.20) compare to Zn (1.65), lower SEP (−2.27 V) compare to Zn (−0.76 V) and higher bond dissociation The simultaneous doping effect of Gadolinium (Gd) and Lithium (Li) on zinc oxide (ZnO) thin-film transistor (TFT) by spray pyrolysis using a ZrO x gate insulator is reported. Li doping in ZnO increases mobility significantly, whereas the presence of Gd improves the stability of the device. The Gd ratio in ZnO is varied from 0% to 20% and the Li ratio from 0% to 10%. The optimized ZnO TFT with codoping of 5% Li and 10% Gd exhibits...

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Section: Resultsmentioning

confidence: 99%

Section: Wwwadvelectronicmatdementioning

confidence: 99%

See 1 more Smart Citation

Extremely Stable, High Performance Gd and Li Alloyed ZnO Thin Film Transistor by Spray Pyrolysis

Saha

Bukke

Jang

2020

Adv Elect Materials

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“…A high areal capacitance of 410 nF/cm 2 is observed in Figure 3(b). At 10000 Hz, there is no obvious change in capacitance, indicating denser M-O bonding formation and lower defect densities, such as hydroxyl group, in the thin film [22].…”

Section: Resultsmentioning

confidence: 99%

“…Too much Hf doped in ZnO thin film would distort the ZnO lattice and deteriorate the electric properties of TFTs. Figure 4(b) shows the XRD patterns of Hf-ZnO thin films with wurtzite structure [22]. The space group is P63mc.…”

Section: Resultsmentioning

confidence: 99%

Low-Voltage Hf-ZnO Thin Film Transistors With Ag Nanowires Gate Electrode and Their Application in Logic Circuit

Yang

et al. 2020

IEEE J. Electron Devices Soc.

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The high performance Hf doped ZnO (Hf-ZnO) flexible thin film transistors (TFTs) were fabricated using Ag NWs as gate electrode and high-k HfO 2 as dielectric. The field effect mobility of Hf-ZnO is 14.7 cm 2 /Vs, I on /I off ratio is more than 10 6 , and the subthreshold swing is about 0.26 V/dec. Furthermore, after 5000 bending cycles test, the TFTs with Ag NWs still maintain a superior performance, such as the high mobility of 12.6 cm 2 /Vs and the small subthreshold swing of 0.33 V/dec. The operating voltage of Hf-ZnO is only 5 V, showing the great potential of application in low-powered devices. We also fabricated the resistor-loaded inverter based on the flexible TFTs. The shift of input voltage is negligible with different supplied voltages, indicating the highly-stable property of the inverter. As a result, the low consumption optoelectronics provide great inspiration for researchers to construct the next generation high performance wearable and flexible devices. INDEX TERMS Low-voltage, Ag nanowire, transistors, logic circuit.

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Characteristics of ALD‐ZnO Thin Film Transistor Using H₂O and H₂O₂ as Oxygen Sources

Yang

Bahrami

Ding

et al. 2022

Adv Materials Inter

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ZnO thin films are deposited by atomic layer deposition (ALD) using diethylzinc as the Zn source and H2O and H2O2 as oxygen sources. The oxidant‐ and temperature‐dependent electrical properties and growth characteristics are systematically investigated. Materials analysis results suggest that H2O2 provides an oxygen‐rich environment so that the oxygen vacancies (VO) is suppressed, implying a lower carrier concentration and a higher resistivity. The lower growth rate makes it possible for the ZnO thin films to grow along the lower surface energy direction of <002>, leading to a lower Hall mobility. Furthermore, the ZnO semiconductor is integrated into thin film transistor (TFT) devices and the electrical properties are analyzed. The TFT with H2O2‐ZnO grown at 150 °C shows good electrical properties, such as a high field‐effect mobility of 10.7 cm2 V–1 s–1, a high ratio Ion/Ioff of 2 × 107, a sharp subthreshold swing of 0.25 V dec–1, and a low trapping state (Ntrap) of 2.77 × 1012 eV–1 cm–2, which provides a new pathway to optimize the performance of metal‐oxide electronics.

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Enhanced Stability in Zr-Doped ZnO TFTs With Minor Influence on Mobility by Atomic Layer Deposition

Cited by 34 publications

References 34 publications

Extremely Stable, High Performance Gd and Li Alloyed ZnO Thin Film Transistor by Spray Pyrolysis

Extremely Stable, High Performance Gd and Li Alloyed ZnO Thin Film Transistor by Spray Pyrolysis

Low-Voltage Hf-ZnO Thin Film Transistors With Ag Nanowires Gate Electrode and Their Application in Logic Circuit

Characteristics of ALD‐ZnO Thin Film Transistor Using H₂O and H₂O₂ as Oxygen Sources

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Enhanced Stability in Zr-Doped ZnO TFTs With Minor Influence on Mobility by Atomic Layer Deposition

Cited by 34 publications

References 34 publications

Extremely Stable, High Performance Gd and Li Alloyed ZnO Thin Film Transistor by Spray Pyrolysis

Extremely Stable, High Performance Gd and Li Alloyed ZnO Thin Film Transistor by Spray Pyrolysis

Low-Voltage Hf-ZnO Thin Film Transistors With Ag Nanowires Gate Electrode and Their Application in Logic Circuit

Characteristics of ALD‐ZnO Thin Film Transistor Using H2O and H2O2 as Oxygen Sources

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Characteristics of ALD‐ZnO Thin Film Transistor Using H₂O and H₂O₂ as Oxygen Sources