ZrOx Negative Capacitance Field-Effect Transistor with Sub-60 Subthreshold Swing Behavior

Abstract

Here we report the ZrOx-based negative capacitance (NC) FETs with 45.06 mV/decade subthreshold swing (SS) under ± 1 V VGS range, which can achieve new opportunities in future voltage-scalable NCFET applications. The ferroelectric-like behavior of the Ge/ZrOx/TaN capacitors is proposed to be originated from the oxygen vacancy dipoles. The NC effect of the amorphous HfO2 and ZrOx films devices can be proved by the sudden drop of gate leakage, the negative differential resistance (NDR) phenomenon, the enhancement of IDS and sub-60 subthreshold swing. 5 nm ZrOx-based NCFETs achieve a clockwise hysteresis of 0.24 V, lower than 60 mV/decade SS and an 12% IDS enhancement compared to the control device without ZrOx. The suppressed NC effect of Al2O3/HfO2 NCFET compared with ZrOx NCFET is related to the partial switching of oxygen vacancy dipoles in the forward sweeping due to negative interfacial dipoles at the Al2O3/HfO2 interface.

Background

As complementary metal oxide semiconductor (CMOS) devices scaling down constantly, the integrated circuit (IC) technique has entered into the era of “more than Moore era”. The driving force of IC industry and technology becomes the reduction of power consumption, instead of the miniaturization of transistors [1, 2]. However, the Boltzmann tyranny of MOSFETs, more than 60 mV/decade SS has restricted the energy/power efficiency [3]. In recent years, many proposed novel devices have the ability to achieve sub-60 mV/decade threshold swing, including impact ionization MOSFETs, tunnel FETs and NCFETs [4,5,6,7]. Due to the simple structure, the steep SS and improved drive current, NCFETs with a ferroelectric (FE) film have been regarded as an attractive alternative among these emerging devices [8,9,10]. The reported experiments on NCFETs mainly include PbZrTiO3 (PZT), P(VDF-TrFE) and HfZrOx (HZO) [11,12,13,14,15,16,17]. However, the high process temperature and undesired gate leakage current along the grain boundaries of polycrystalline ferroelectric materials have restricted their development for the state-of-the-art technology nodes [18,19,20,21,22,23,24,25,26]. Recently, ferroelectricity in the amorphous Al2O3 and ZrOx films enabled by the voltage-modulated oxygen vacancy dipoles has been investigated [27,28,29]. Compared with the crystalline counterpart, the amorphous ferroelectric-like films have significant advantages in reduced process temperature and leakage current. Thus, there are mass researches on FeFETs with amorphous gate insulator for the non-volatile memory and analog synapse applications [27, 30,31,32,33,34]. However, the systematical investigation on one-transistor ZrOx-based NCFET has not been carried out.

In this work, Ge NCFETs with 5 nm ZrOx ferroelectric dielectric layer and 5 nm Al2O3/HfO2 ferroelectric dielectric layer have been proposed, respectively. We experimentally observed sub-60 mV/decade steep slope in ZrOx (5 nm) NCFET, which can be attributed to the NC effect of ZrOx ferroelectric layer. And we analyzed the polarization P as function of applied voltage V for the Ge/ZrOx/TaN capacitors. The ferroelectric-like behavior of the Ge/ZrOx/TaN capacitors is induced by the voltage-induced oxygen vacancy dipoles. Moreover, we attributed the improved IDS and the sudden drop of IG in the Al2O3/HfO2 NCFETs and ZrOx NCFETs to the NC effect. We also observed the NDR phenomenon in the Al2O3/HfO2 NCFETs and ZrOx NCFETs. In addition, we further analyzed the physical mechanism of interfacial dipoles-induced decreased NC effect in the Al2O3/HfO2 NCFET. The ZrOx NCFETs with sub-60 mV/decade steep slope, improved drain voltage and low operating voltage will be suit for the design of NCFETs with low power consumption in the “more than Moore era”.

Methods

Key process steps for NCFETs with ZrOx and Al2O3/HfO2 fabrication are shown in Fig. 1a. Different gate dielectric insulators, including Al2O3/amorphous HfO2 (5 nm) films and amorphous ZrOx (4.2 nm) films were grown on n-Ge (001) substrates by atomic layer deposition (ALD) at 300 °C. TMA, TDMAHf, TDMAZr and H2O vapor were used as the precursors of Al, Hf, Zr and O, respectively. The pulse time and purge time of the precursors of Hf and Zr are 1.6 s and 8 s, respectively. The pulse time and purge time of the precursors of Al are 0.2 s and 8 s, respectively. A TaN top gate electrode was then deposited on HfO2 or ZrOx surfaces by reactive sputtering. Source/drain (S/D) regions were defined by lithography patterning and dry etching. After that, boron (B+) and nickel (Ni) was deposited in source/drain (S/D) regions. Finally, rapid thermal annealing (RTA) at 350 °C for 30 s in a 108 Pa nitrogen ambient was carried out. Figure 1b, d show the schematics of the fabricated Al2O3/HfO2 NCFETs and ZrOx NCFETs. High-resolution transmission electron microscope (HRTEM) image in Fig. 1c depicts the amorphous HfO2 (5 nm) film on Ge (001) with Al2O3 interfacial layer. HRTEM image in Fig. 1e depicts the amorphous ZrOx (4.2 nm) film on Ge (001). The C–V curve of ZrOx NCFETs and the X-ray photoelectron spectra (XPS) of TaN/ZrOx (4.2 nm)/Ge capacitors were measured in Additional file 1: Fig. S1.

Fig. 1
figure1

a Key process steps for the fabrication of the Al2O3/5 nm HfO2 NCFETs and 4.2 nm ZrOx NCFETs. b Schematics and c HRTEM images of the fabricated ZrOx NCFETs. d Schematics and e HRTEM images of the fabricated Al2O3/HfO2 NCFETs

Results and Discussion

Figure 2a shows the measured curves of polarization P v.s. applied voltage V characteristics for the Ge/ZrOx/TaN capacitors at 3.3 kHz. The gate length (LG) of the capacitors are 8 μm. It is observed that the remnant polarization Pr of the Ge/ZrOx/TaN capacitors can be enhanced with larger sweeping range of V. The ferroelectric-like behavior of the amorphous ZrOx film in the Fig. 2a is proposed to be originated from the voltage-driven oxygen vacancy dipoles [35]. Figure 2b shows the measured P–V curves for the Ge/ZrOx/TaN capacitors under different frequencies from 200 to 10 kHz. We can see that the ferroelectric-like behavior of the amorphous ZrOx film remain stable for all frequencies. However, the Pr of the amorphous ZrOx film is reduced with the increased frequencies. This phenomenon can be explained by the incomplete dipoles switching under high measurement frequencies [36, 37]. As measurement frequencies increasing, the time for the direction change of electric field in the amorphous ZrOx film decreases. Thus, part of oxygen vacancy diploes switching is incomplete, providing decreased Pr.

Fig. 2
figure2

Measured P versus V characteristics of the 4.2 nm ZrOx capacitors with a different sweeping ranges of V and b different measurement frequences

Figure 3a shows the measured IDSVGS curves of a ferroelectric Al2O3/HfO2 NCFET at the VDS of − 0.05 V and − 0.5 V. The LG of the devices is 3 μm. The hysteresis loops of 0.14 V (VDS = − 0.05 V, Ids = 1 nA/μm) and 0.08 V (VDS = − 0.5 V, Ids = 1 nA/μm) are demonstrated, respectively. The clockwise hysteresis loops are attributed to the migration of oxygen vacancies and accompanied negative charges. The oxygen vacancy dipoles accumulate (deplete) in the Ge/Al2O3 interface under positive (negative) VGS. Therefore, the threshold voltage (VTH) increases (decreases) under forward (reverse) sweeping of gate voltages. As shown in Fig. 3b, the output characteristics of the Al2O3/HfO2 NCFET and the control FET are compared. The saturation current of the Al2O3/HfO2 NCFET exceeds 26 μA/μm, with a rise of 23% compared to that of the control FET at |VGSVTH| =|VDS|= 0.8 V. The current enhancement is induced by the increased inversion charge intensity (Qinv) in the reverse polarization electric field and the amplification of surface potential [38, 39]. In addition to current enhancement, the obtained obvious NDR proves the NC effect of the amorphous HfO2 film. The NDR effect is caused by the incomplete switching of oxygen vacancy dipoles due to the coupling of drain-to-channel as VDS increases [40, 41]. Figure 3c compares the measured gate leakage IGVGS curves for the 5 nm Al2O3/HfO2 NCFET at the VDS of − 0.05 V and − 0.5 V. The sudden drops of IG only during the reverse sweeping indicate the decreased voltage in the amorphous HfO2 film and the amplication of surface potential [42]. The absence of NC effect during the forward sweeping is caused by the partical switching of oxygen vacancy dipoles in the amorphous HfO2 film [43]. The different ability to contain oxygen atoms between Al2O3 and HfO2 layer leads to oxygen redistribution and negative interfacial dipoles at the Al2O3/HfO2 interface [44, 45]. Due to the presence of negative interfacial dipoles, it is difficult for the amorphous HfO2 film to realize complete polarization switching (NC effect) in the forward sweeping (Additional file 1).

Fig. 3
figure3

a Measured IDSVGS curves of the 5 nm HfO2 NCFET when VDS = − 0.5 V and VDS = − 0.05 V. b Measured IDSVDS curves of the HfO2 NCFET and the control MOSFET. c Measured IGVGS curves of the 5 nm HfO2 NCFET when VDS = − 0.5 V and VDS = − 0.05 V

Figure 4a shows the measured transfer curves of a ferroelectric ZrOx NCFET at the VDS of − 0.05 V and − 0.5 V. The LG of the two devices are 4 μm. The clockwise hysteresis loops of 0.24 V (VDS = − 0.05 V, Ids = 1 nA/μm) and 0.14 V (VDS = − 0.5 V, IDS = 1 nA/μm) are demonstrated, respectively. As shown in Fig. 4b, the output characteristics of the ZrOx NCFET and the control FET are compared. The saturation current of the ZrOx NCFET exceeds 30 μA/μm, with a rise of 12% compared to that of the control FET at |VGSVTH| =|VDS|= 1 V. The improved current enhancement and more obvious NDR indicate the enhanced NC effect of the amorphous ZrOx film (5 nm) contrast to that of 5 nm HfO2 film. Figure 4c compares the measured gate leakage IGVGS curves for the 5 nm ZrOx NCFET at the VDS of − 0.05 V and − 0.5 V. Compared to the sudden IG drops of Al2O3/HfO2 NCFET only during reverse sweeping in Fig. 3c, the sudden drops of IG both in forward and reverse sweeping in Fig. 4c also prove the enhanced NC effect in the amorphous ZrOx film.

Fig. 4
figure4

a Measured IDSVGS curves of the 5 nm ZrOx NCFET when VDS = − 0.5 V and VDS = − 0.05 V. b Measured IDSVDS curves of the ZrOx NCFET and the control MOSFET demonstraing the obvious NDR phenomenon. c Measured IGVGS curves of the 5 nm ZrOx NCFET when VDS = − 0.5 V and VDS = − 0.05 V

Figure 5a, b shows the point SS as function of IDS for the Al2O3/HfO2 and ZrOx NCFET at the VDS of − 0.05 V and− 0.5 V. As shown in Fig. 5b, sub-60 mV/decade subthreshold swing (SS) can be achieved during forward or reverse sweeping of VGS at the VDS of− 0.05 V and− 0.5 V. When VDS is− 0.05 V, a point forward SS of 45.1 mV/dec and a point reverse SS of 55.2 mV/dec were achieved. When VDS is− 0.5 V, a point forward SS of 51.16 mV/dec and a point reverse SS of 46.52 mV/dec were achieved. Due to the different ability of scavenging effect for the Al2O3/HfO2 and ZrOx layer, the partical dipoles switching is caused in the Al2O3/HfO2 NCFET. Therefore, the more obvious NC effect with sub-60 mV/decade SS is achieved in 5 nm ZrOx NCFET.

Fig. 5
figure5

Point SS as a function of IDS for the a Al2O3/5 nm HfO2 NCFETs and b 5 nm ZrOx NCFETs

Conclusions

We report the demonstration of ferroelectric NC ZrOx pFETs with the sub-60 mV/decade SS, low operating voltage of 1 V and a hysteresis of less than 60 mV. The impact of the amorphous ZrOx films on the ferroelectric behavior is explained by the oxygen vacancy dipoles. The improved IDS and NDR phenomenon are also obtained in Al2O3/HfO2 NCFETs and ZrOx NCFETs compared to the control device. The suppressed NC effect of the Al2O3/HfO2 NCFET can be attributed to partical dipole swiching due to interfical dipoles at the Al2O3/HfO2 interface. The ZrOx NCFETs with sub-60 mV/decade steep slope, improved drain voltage and low operating voltage pave a new way for future low power consumption NCFETs design.

Availability of Data and Materials

The datasets supporting the conclusions of this article are included in the article.

Abbreviations

TaN:

Tantalum nitride

ZrOx :

Zirconium dioxide

TDMAZr:

Tetrakis (dimethylamido) zirconium

P r :

Remnant polarization

E c :

Coercive electric field

MOSFETs:

Metal–oxide–semiconductor field-effect transistors

Ge:

Germanium

ALD:

Atomic layer deposition

B+ :

Boron ion

Al2O3 :

Aluminum oxide

HRTEM:

High-resolution transmission electron microscope

Ni:

Nickel

RTA:

Repaid thermal annealing

I DS :

Drain current

V GS :

Gate voltage

V TH :

Threshold voltage

NCFET:

Negative capacitance field-effect transistor

References

  1. 1.

    Lundstrom MS. The MOSFET revisited: device physics and modeling at the nanoscale. IEEE Int. SOI Conf. 2006;1–3.

  2. 2.

    Sakurai T. Perspectives of low-power VLSI’s. IEICE Trans. Electron. 2004;429–436.

  3. 3.

    Sze SM, Ng KK. Physics of Semiconductor Devices, 3rd Edition. Wiley Inter science; 2006.

  4. 4.

    Baba T (1992) Proposal for surface tunnel transistors. Jpn J Appl Phys 31:4

    Article  Google Scholar 

  5. 5.

    Sarkar D, Xie X, Liu W et al (2015) A subthermionic tunnel field-effect transistor with an atomically thin channel. Nature 526:91–95

    CAS  Article  Google Scholar 

  6. 6.

    Gopalakrishnan K, Griffifin P, Plummer J (2005) Impact ionization MOS (IMOS)-Part I: device and circuit simulations. IEEE Tran Elec Dev 52:69–76

    CAS  Article  Google Scholar 

  7. 7.

    Salahuddin S, Datta S (2008) Use of negative capacitance to provide voltage amplifification for low power nanoscale devices. Nano Lett 8:405–410

    CAS  Article  Google Scholar 

  8. 8.

    Li KS, Chen PG, Lai TY, et al. Sub-60mV-swing negative-capacitance FinFET without hysteresis. In: IEEE international electron devices meeting. 2016.

  9. 9.

    Khan AI, Yeung CW, Hu C, et al. Ferroelectric negative capacitance MOSFET: capacitance tuning and antiferroelectric operation. IEDM Tech Dig. 2011.

  10. 10.

    Salahuddin S, Datta S (2008) Use of negative capacitance to provide voltage amplification for low power nanoscale devices. Nano Lett 8(2):405–410

    CAS  Article  Google Scholar 

  11. 11.

    Dasgupta S, Rajashekhar A, Majumdar K, et al. Sub-kT/q switching in strong inversion in PbZr0.52Ti0.48O3 gated negative capacitance FETs. IEEE J Exploratory Solid-State Comput. Devices Circuits. 2017; 1:43–48.

  12. 12.

    Bakaul S, Serrao C, Lee M et al (2016) Single crystal functional oxides on silicon. Nat Commun 7:10547

    CAS  Article  Google Scholar 

  13. 13.

    Rusu A, Salvatore GA, Jimenez D, et al. Metal–ferroelectric–metal–oxide–semiconductor field effect transistor with sub-60 mV/decade subthreshold swing and internal voltage amplification. Electron Devices Meeting. IEDM Tech Dig. 2010.

  14. 14.

    Jo J, Shin C (2016) Negative capacitance field effect transistor with hysteresis-free sub-60-mV/Decade switching. IEEE Electron Device Lett 37:245–248

    CAS  Article  Google Scholar 

  15. 15.

    Lee MH, Wei YT, Chu KY et al (2015) Steep slope and near non-hysteresis of FETs with antiferroelectric-like HfZrO for low-power electronics. IEEE Electron Device Lett 36:294–296

    CAS  Article  Google Scholar 

  16. 16.

    Cheng CH, Chin A (2014) Low-voltage steep turn-on pMOSFET using ferroelectric high-k gate dielectric. IEEE Electron Device Lett 35:274–276

    CAS  Article  Google Scholar 

  17. 17.

    Lee MH, Chen PG, Liu C, et al. Prospects for ferroelectric HfZrOx FETs with experimentally CET=0.98 nm, SSfor=42 mV/dec, SSrev=28 mV/dec, switch-OFF <0.2 V, and hysteresis-free strategies. In: IEEE international electron devices meeting; 2015.

  18. 18.

    Müller J, Yurchuk E, Schlsser T, et al. Ferroelectricity in HfO2 enables nonvolatile data storage in 28 nm HKMG. In: Symposium on VlSI technology; 2012.

  19. 19.

    Schroeder U, Yurchuk E, Müller J et al (2014) Impact of different dopants on the switching properties of ferroelectric hafnium oxide. Jpn J Appl Phys 53:85–89

    Article  Google Scholar 

  20. 20.

    Mueller S, Muller J, Schroeder U et al (2013) Reliability characteristics of ferroelectric Si:HfO2 thin films for memory applications. IEEE T Device Mat Re 13:93–97

    CAS  Article  Google Scholar 

  21. 21.

    Park MH, Kim HJ, Kim YJ et al (2016) Effect of Zr content on the wake-up effect in Hf1–xZrxO2 films. ACS Appl Mater Inter 8:15466–15475

    CAS  Article  Google Scholar 

  22. 22.

    Schroeder U, Richter C, Park MH et al (2018) Lanthanum-doped hafnium oxide: a robust ferroelectric material. Inorg Chem 57:2752–2765

    CAS  Article  Google Scholar 

  23. 23.

    Chernikova AG, Kozodaev MG, Negrov DV et al (2018) Improved ferroelectric switching endurance of la-doped Hf0.5Zr0.5O2 Thin Films. ACS Appl. Mater. Interfaces 10:2701–2708

    CAS  Article  Google Scholar 

  24. 24.

    Hyuk PM, Hwan LY, Thomas M et al (2018) Review and perspective on ferroelectric HfO2-based thin films for memory applications. MRS Commun 8:795–808

    Article  Google Scholar 

  25. 25.

    Mueller S, Yurchuk E, Slesazeck S, et al. Performance investigation and optimization of Si:HfO2 FeFETs on a 28 nm bulk technology. In: Joint IEEE international symposium on applications of ferroelectric and workshop on piezoresponse force microscopy; 2013;248–51.

  26. 26.

    Zhou J, Zhou Z, Wang X et al (2020) Demonstration of ferroelectricity in Al-doped HfO2 with a low thermal budget of 500 °C. IEEE Electron Device Lett 41:1130–1133

    CAS  Google Scholar 

  27. 27.

    Liu H, Peng Y, Han G et al (2020) ZrO2 ferroelectric field-effect transistors enabled by the switchable oxygen vacancy dipoles. Nanoscale Res Lett 15:120

    CAS  Article  Google Scholar 

  28. 28.

    Peng Y, Han G, Liu F, et al. Non-Volatile Field-Effect Transistors Enabled by Oxygen Vacancy Related Dipoles for Memory and Synapse Applications. IEEE Electron Device Lett. 2020.

  29. 29.

    Peng Y, Han G, Liu F et al (2020) Ferroelectric-like behavior originating from oxygen vacancy dipoles in amorphous film for non-volatile memory. Nanoscale Res Lett 15:134

    CAS  Article  Google Scholar 

  30. 30.

    Park MH, Kim HJ, Kim YJ et al (2014) Thin HfxZr1xO2 films: a new lead-free system for electrostatic supercapacitors with large energy storage density and robust thermal stability. Adv Energy Mater 4:1400610

    Article  Google Scholar 

  31. 31.

    Schroeder U, Yurchuk E, Mueller J et al (2014) Impact of different dopants on the switching properties of ferroelectric hafnium oxide. Jpn J Appl Phys 53:08LE02

    Article  Google Scholar 

  32. 32.

    Peng Y, Xiao W, Liu F et al (2020) Non-volatile field-effect transistors enabled by oxygen vacancy related dipoles for memory and synapse applications. IEEE Electron Device Lett 67:3632–3636

    CAS  Article  Google Scholar 

  33. 33.

    Peng Y, Han G, Liu F et al (2020) Ferroelectric-like behavior originating from oxygen vacancy dipoles in amorphous film for non-volatile memory. Nanoscale Res Lett 5:134

    Article  Google Scholar 

  34. 34.

    Zhang S, Liu Y, Zhou J et al (2020) Low voltage operating 2D MoS2 ferroelectric memory transistor with Hf1xZrxO2 gate structure. Nanoscale Res Lett 15:157

    CAS  Article  Google Scholar 

  35. 35.

    Glinchuk MD, Morozovska AN, Lukowiak A et al (2020) Possible electrochemical origin of ferroelectricity in HfO2 thin films. J Alloy Compod 830:153628

    CAS  Article  Google Scholar 

  36. 36.

    Ishibashi Y, Orihara H (1995) A theory of D–E hysteresis loop. Integr Ferroelectr 9:57–61

    Article  Google Scholar 

  37. 37.

    Scott JF, Dawber M (2000) Atomic-scale and nanoscale self-patterning in ferroelectric thin films. AIP Conf Proc 535:129

    CAS  Article  Google Scholar 

  38. 38.

    Chen HP, Lee VC, Ohoka A et al (2011) Modeling and design of ferroelectric MOSFETs. IEEE Trans Electron Devices 58:2401–2405

    CAS  Article  Google Scholar 

  39. 39.

    Zhou J, Peng Y, Han G et al (2017) Hysteresis reduction in negative capacitance ge pfets enabled by modulating ferroelectric properties in HfZrOx. IEEE J Electron Dev 6:41–48

    Google Scholar 

  40. 40.

    Saha AK, Sharma P, Dabo I, et al. Ferroelectric transistor model based on self-consistent solution of 2D Poisson's, non-equilibrium Green's function and multi-domain Landau Khalatnikov equations. In: IEEE international electron devices meeting. 2018.

  41. 41.

    Zhou J, Han G, Li J et al (2018) Negative differential resistance in negative capacitance FETs. IEEE Electron Device Lett 39:622–625

    CAS  Article  Google Scholar 

  42. 42.

    Zhou J, Han G, Li Q, et al. Ferroelectric HfZrOx Ge and GeSn PMOSFETs with Sub-60 mV/decade subthreshold swing, negligible hysteresis, and improved Ids. In: IEEE international electron devices meeting. 2017.

  43. 43.

    Sharma P, Tapily K, Saha AK, et al. Impact of total and partial dipole switching on the switching slope of gate-last negative capacitance FETs with ferroelectric hafnium zirconium oxide gate stack. In: Symposium on VLSI technology. 2017.

  44. 44.

    Lin L, Robertson J (2011) Atomic mechanism of electric dipole formed at high-K: SiO2 interface. J Appl Phys 109:9

    Google Scholar 

  45. 45.

    Sharia O, Demkov AA, Bersuker G et al (2007) Theoretical study of the insulator/insulator interface: band alignment at the SiO2/HfO2 junction. Phys Rev B 75:3

    Article  Google Scholar 

Download references

Acknowledgements

Not applicable.

Funding

The authors acknowledge support from the National Key Research and Development Project (Grant No. 2018YFB2202800, 2018YFB2200500) and the National Natural Science Foundation of China (Grant No. 62025402, 62090033, 91964202, 92064003, 61874081, 61851406, 62004149 and 62004145).

Author information

Affiliations

Authors

Contributions

SQZ and HL drafted the manuscript and carried out the experiments. YL designed the experiments. YL and JRZ helped to revise the manuscript. YH and GQH supported the study. All the authors read and approved the final manuscript.

Corresponding author

Correspondence to Yan Liu.

Ethics declarations

Competing interests

The authors declare that they have no competing interests.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Additional file 1

. From the C–V curve of ZrOx NCFETs in Fig. S1 (a), we can see that the threshold voltage of the ZrOx NCFETs is around 0.5 V. From the XPS of TaN/ZrOx (4.2 nm)/Ge capacitors in Fig. S1 (b), we can see that a TaOx interfacial layer formed in the TaN/ZrOx interface and oxygen vacancies (ZrOx) in ZrOx because of the scavenging effect.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Zhang, S., Liu, H., Zhou, J. et al. ZrOx Negative Capacitance Field-Effect Transistor with Sub-60 Subthreshold Swing Behavior. Nanoscale Res Lett 16, 21 (2021). https://doi.org/10.1186/s11671-020-03468-w

Download citation

Keywords

  • Amorphous ZrOx
  • Ferroelectric
  • FET
  • Subthreshold swing
  • Negative capacitance