Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Amorphous indium tin oxide transistors for power amplification above 10 GHz

Nature Electronics volume 8, pages 803–809 (2025)Cite this article

Subjects

Abstract

Amorphous oxide semiconductors could be used as thin channel materials in future back-end-of-line-compatible electronics. However, thin body amorphous materials suffer from Joule heating due to the strong scattering of electrons and phonons from extensive local disorder, which can lead to device failure in high-speed power-intensive applications. Here we show that the electrical and thermal transport properties of amorphous indium tin oxide can be enhanced using a silicon carbide substrate. Using this approach, we create top-gate transistors that have a channel length of 120 nm and exhibit negligible performance degradation under high electric fields and temperatures of up to 125 °C. We show that the devices can offer a cutoff frequency of 103 GHz and a maximum oscillation frequency of 125 GHz. Furthermore, our indium tin oxide power amplifiers provide a high output power density of 0.69 W mm−1 and a power-added efficiency of 24.1% at 12 GHz.

Access through your institution
Buy or subscribe

This is a preview of subscription content, access via your institution

Access options

Access through your institution

Buy this article

  • Purchase on SpringerLink
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Thermal conductivity of the materials and device heat dissipation.
Fig. 2: Extrinsic RF performance of top-gate ITO transistors on SiO2 and SiC substrates.
Fig. 3: High-temperature stability of top-gate ITO transistor on SiC substrate.
Fig. 4: De-embedded RF performance of top-gate ITO transistors on SiC substrates.
Fig. 5: Load-pull characterization of a top-gate ITO transistor on an SiC substrate.

Similar content being viewed by others

Data availability

The data that support the plots within this paper are available from the corresponding author upon reasonable request.

References

  1. Li, S. et al. Nanometre-thin indium tin oxide for advanced high-performance electronics. Nat. Mater. 18, 1091–1097 (2019).

    Article  Google Scholar 

  2. Li, Q. et al. BEOL-compatible high-performance a-IGZO transistors with record high Ids,max = 1,207 μA/μm and on-off ratio exceeding 1011 at Vds = 1 V. In Proc. 2022 IEEE International Electron Devices Meeting (IEDM) 42–45 (IEEE, 2022).

  3. Hu, Q. et al. True nonvolatile high-speed DRAM cells using tailored ultrathin IGZO. Adv. Mater. 35, 2210554 (2023).

    Article  Google Scholar 

  4. Ye, H. et al. Double-gate W-doped amorphous indium oxide transistors for monolithic 3D capacitorless gain cell eDRAM. In Proc. 2020 IEEE International Electron Devices Meeting (IEDM) 613–616 (IEEE, 2020).

  5. Belmonte, A. et al. Tailoring IGZO-TFT architecture for capacitorless DRAM, demonstrating >103 s retention, >1011 cycles endurance and Lg scalability down to 14 nm. In Proc. 2021 IEEE International Electron Devices Meeting (IEDM) 226-229 (IEEE, 2021).

  6. Duan, X. et al. Novel vertical channel-all-around (CAA) IGZO FETs for 2T0C DRAM with high density beyond 4F2 by monolithic stacking. In Proc. 2021 IEEE International Electron Devices Meeting (IEDM) 222–225 (IEEE, 2021).

  7. Hu, Q. et al. Optimized IGZO FETs for capacitorless DRAM with retention of 10 ks at RT and 7 ks at 85 °C at zero Vhold with sub-10 ns speed and 3-bit operation. In Proc. 2022 IEEE International Electron Devices Meeting (IEDM) 619–622 (IEEE, 2022).

  8. Wang, C. et al. Extremely scaled bottom gate a-IGZO transistors using a novel patterning technique achieving record high Gm of 479.5 μS/μm (VDS of 1 V) and fT of 18.3 GHz (VDS of 3 V). In Proc. 2022 IEEE Symposium on VLSI Technology 294–295 (IEEE, 2022).

  9. Zheng, D. et al. Ultrathin atomic-layer-deposited In2O3 radio-frequency transistors with record high fT of 36 GHz and BEOL compatibility. In Proc. 2023 IEEE Symposium on VLSI Technology T11-1 (IEEE, 2023).

  10. Hu, Q. et al. Ultrashort 15-nm flexible radio frequency ITO transistors enduring mechanical and temperature stress. Sci. Adv. 8, eade4075 (2022).

    Article  Google Scholar 

  11. Chasin, A. et al. Understanding and modelling the PBTI reliability of thin-film IGZO transistors. In Proc. 2021 IEEE International Electron Devices Meeting (IEDM) 657–660 (IEEE, 2021).

  12. Kong, Q. et al. New insights into the impact of hydrogen evolution on the reliability of IGZO FETs: experiment and modeling. In Proc. 2022 IEEE International Electron Devices Meeting (IEDM) 699–702 (IEEE, 2022).

  13. Zhang, J. et al. Back-end-of-line-compatible scaled InGaZnO transistors by atomic layer deposition. IEEE Trans. Electron Devices 69, 147–151 (2023).

    Google Scholar 

  14. Shen, Y. et al. Gate stack engineering in MoS2 field-effect transistor for reduced channel doping and hysteresis effect. Adv. Electron. Mater. 7, 2000395 (2021).

    Article  Google Scholar 

  15. Si, M., Lin, Z., Chen, Z. & Ye, P. D. High-performance atomic-layer-deposited indium oxide 3-D transistors and integrated circuits for monolithic 3-D integration. IEEE Trans. Electron Devices 68, 6605–6609 (2021).

    Article  Google Scholar 

  16. Wahid, S. et al. First-demonstration of top-gated ITO transistors: effect of channel passivation. In Proc. 2022 Device Research Conference (DRC) 1–2 (2022).

  17. Gu, C. et al. High-performance short-channel top-gate indium-tin-oxide transistors by optimized gate dielectric. IEEE Electron Device Lett. 44, 837–840 (2023).

    Article  Google Scholar 

  18. Liao, P. et al. Thermal studies of BEOL-compatible top-gated atomically thin ALD In2O3 FETs. In Proc. 2022 IEEE Symposium on VLSI Technology 322–323 (IEEE, 2022).

  19. Jeong, C., Datta, S. & Lundstrom, M. Thermal conductivity of bulk and thin-film silicon: a Landauer approach. J. Appl. Phys. 111, 093708 (2012).

    Article  Google Scholar 

  20. Kwon, S., Wingert, M. C., Zheng, J., Xiang, J. & Chen, R. Thermal transport in Si and Ge nanostructures in the ‘confinement’ regime. Nanoscale 8, 13155–13167 (2016).

    Article  Google Scholar 

  21. Zhou, W. et al. Thermal conductivity of amorphous materials. Adv. Funct. Mater. 30, 1903829 (2020).

    Article  Google Scholar 

  22. Scott, E. A. et al. Simultaneous thickness and thermal conductivity measurements of thinned silicon from 100 nm to 17 μm. Appl. Phys. Lett. 118, 202108 (2021).

    Article  Google Scholar 

  23. Jugdersuren, B. et al. The effect of ultrasmall grain sizes on the thermal conductivity of nanocrystalline silicon thin films. Commun. Phys. 4, 169 (2021).

    Article  Google Scholar 

  24. Yoshikawa, T. et al. Thermal conductivity of amorphous indium-gallium-zinc oxide thin films. Appl. Phys. Express 6, 021101 (2013).

    Article  Google Scholar 

  25. Kim, C. K. et al. Electrothermal annealing (ETA) method to enhance the electrical performance of amorphous-oxide-semiconductors (AOS) thin-film transistors (TFTs). ACS Appl. Mater. Interfaces 8, 23820–23826 (2016).

    Article  Google Scholar 

  26. Olson, D. H. et al. Size effects on the cross-plane thermal conductivity of transparent conducting indium tin oxide and fluorine tin oxide thin films. IEEE Trans. Compon. Packag. Manuf. Technol. 9, 51–57 (2019).

    Article  Google Scholar 

  27. Cai, L. et al. Investigation of self-heating effect on stacked nanosheet GAA transistors. In Proc. 2018 International Symposium on VLSI Technology, Systems and Application (VLSI-TSA) 1–2 (2018).

  28. Charnas, A. et al. Record RF performance of ultra-thin indium oxide transistors with buried-gate structure. In Proc. 2022 Device Research Conference (DRC) 1–2 (2022).

  29. Khanna, A. et al. BEOL compatible ferroelectric routers for rum-time reconfigurable compute-in-memory accelerators. In Proc. 2022 IEEE Symposium on VLSI Technology 240–241 (IEEE, 2022).

  30. Liao, P., Si, M., Zhang, Z., Lin, Z. & Ye, P. D. Realization of maximum 2 A/mm drain current on top-gate atomic-layer-thin indium oxide transistors by thermal engineering. IEEE Trans. Electron Devices 69, 147–151 (2021).

    Article  Google Scholar 

  31. Liao, P. et al. Transient thermal and electrical co-optimization of BEOL top-gated ALD In2O3 FETs on various thermally conductive substrate including diamond. In Proc. 2022 IEEE International Electron Devices Meeting (IEDM) 286–289 (IEEE, 2022).

  32. Yu, X. et al. High-voltage β-Ga2O3 RF MOSFETs with a shallowly-implanted 2DEG-like channel. IEEE Electron Device Lett. 44, 1060–1063 (2023).

    Article  Google Scholar 

  33. Pop, E., Dutton, R. & Goodson, K. Thermal analysis of ultra-thin body scaling. In Proc. 2003 IEEE International Electron Devices Meeting (IEDM) 883–886 (IEEE, 2003).

  34. Qian, X., Zhou, J. & Chen, G. Phonon-engineered extreme thermal conductivity materials. Nat. Mater. 20, 1188–1201 (2021).

    Article  Google Scholar 

  35. Salamin, S., Santen, V. M. V., Rapp, M., Henkel, J. & Amrouch, H. Minimizing excess timing guard banding under transistor self-heating through biasing at zero-temperature coefficient. IEEE Access 9, 30687–30697 (2021).

    Article  Google Scholar 

  36. Hu, Q. et al. First demonstration of top-gate indium-tin-oxide RF transistors with record high cut-off frequency of 48 GHz, Id of 2.32 mA/μm and gm of 900 μS/μm on SiC substrate with superior reliability at 85 °C. In Proc. 2023 IEEE International Electron Devices Meeting (IEDM) 39.6 (IEEE, 2023).

  37. Teppati, V., Ferrero, A. & Sayed, M. Modern RF and Microwave Measurement Techniques (Cambridge Univ. Press, 2013).

  38. Liao, L. et al. High-speed graphene transistors with a self-aligned nanowire gate. Nature 467, 305–308 (2010).

    Article  Google Scholar 

  39. Shi, H. et al. Radiofrequency transistors based on aligned carbon nanotubes arrays. Nat. Electron. 4, 405–415 (2021).

    Article  Google Scholar 

  40. Wu, Y. et al. 200 GHz maximum oscillation frequency in CVD graphene radio frequency transistors. ACS Appl. Mater. Interfaces 8, 25645–25649 (2016).

    Article  Google Scholar 

  41. Zheng, D. et al. First demonstration of BEOL-compatible ultrathin atomic-layer-deposited InZnO transistors with GHz operation and record high bias-stress stability. In Proc. 2022 IEEE International Electron Devices Meeting (IEDM) 78–81 (IEEE, 2022).

  42. Green, A. J. et al. β-Ga2O3 MOSFETs for radio frequency operation. IEEE Electron Device Lett. 38, 790–793 (2017).

    Article  Google Scholar 

  43. Chabak, K. W. et al. Sub-micron gallium oxide radio frequency field-effect transistors. In Proc. 2018 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP) 1–3 (IEEE, 2018).

  44. Zhang, Y. et al. Demonstration of high mobility and quantum transport in modulation-doped β-(AlxGa1−x)2O3/Ga2O3 heterostructures. Appl. Phys. Lett. 112, 173502 (2018).

    Article  Google Scholar 

  45. Zhang, Y. et al. Evaluation of low-temperature saturation velocity in β-(AlxGa1−x)2O3/Ga2O3 modulation-doped field-effect transistors. IEEE Trans. Electron Devices 66, 1574–1578 (2019).

    Article  Google Scholar 

  46. Lv, Y. et al. Oxygen annealing impact on β-Ga2O3 MOSFETs: Improved pinch-off characteristic and output power density. Appl. Phys. Lett. 117, 133503 (2020).

    Article  Google Scholar 

  47. Moser, N. et al. Toward high voltage radio frequency devices in β-Ga2O3. Appl. Phys. Lett. 117, 242101 (2020).

    Article  Google Scholar 

  48. Saha, C. N. et al. Scaled β-Ga2O3 thin channel MOSFET with 5.4 MV/cm average breakdown field and near 50 GHz fMAX. Appl. Phys. Lett. 122, 182106 (2023).

    Article  Google Scholar 

  49. Yu, X. et al. Heterointegrated Ga2O3-on-SiC RF MOSFETs with fT/fmax of 47/51 GHz by ion-cutting process. IEEE Electron Device Lett. 44, 1951–1954 (2023).

    Article  Google Scholar 

  50. Singh, M. et al. Pulsed large signal RF performance of field-plated Ga2O3 MOSFETs. IEEE Electron Device Lett. 39, 1572–1575 (2018).

    Article  Google Scholar 

  51. Moser, N. A. et al. Pulsed power performance of β-Ga2O3 MOSFETs at L-band. IEEE Electron Device Lett. 41, 989–992 (2020).

    Article  Google Scholar 

  52. Schwierz, F. & Liou, J. J. Modern Microwave Transistors: Theory, Design and Performance (Wiley, 2003).

Download references

Acknowledgements

This work was supported by the National Key Research and Development Program of China (grant no. 2020AAA0109005) and the National Natural Science Foundation of China (grant nos. 62425402, 92364203 and 62090034).

Author information

Authors and Affiliations

  1. School of Integrated Circuits and Beijing Advanced Innovation Center for Integrated Circuits, Peking University, Beijing, China

    Qianlan Hu, Yuzhe Zhu, Chengru Gu, Shiyuan Liu, Ru Huang & Yanqing Wu

  2. Wuhan National High Magnetic Field Center and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China

    Shenwu Zhu & Yanqing Wu

Authors
  1. Qianlan Hu
    View author publications

    Search author on:PubMed Google Scholar

  2. Shenwu Zhu
    View author publications

    Search author on:PubMed Google Scholar

  3. Yuzhe Zhu
    View author publications

    Search author on:PubMed Google Scholar

  4. Chengru Gu
    View author publications

    Search author on:PubMed Google Scholar

  5. Shiyuan Liu
    View author publications

    Search author on:PubMed Google Scholar

  6. Ru Huang
    View author publications

    Search author on:PubMed Google Scholar

  7. Yanqing Wu
    View author publications

    Search author on:PubMed Google Scholar

Contributions

Y.W. proposed and supervised the project. Q.H. fabricated the devices and carried out the electrical measurements. S.Z., Y.Z. and C.G. contributed to the d.c. characterizations. S.L. contributed to the device structure characterizations. Q.H., Y.W. and R.H. analysed the data. Q.H. and Y.W. co-wrote the paper. All authors contributed to discussions on the paper.

Corresponding author

Correspondence to Yanqing Wu.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Electronics thanks Tiangui You and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

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

Supplementary information

Supplementary Information

Supplementary Figs. 1–8, Notes 1–10 and Tables 1–3.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Hu, Q., Zhu, S., Zhu, Y. et al. Amorphous indium tin oxide transistors for power amplification above 10 GHz. Nat Electron 8, 803–809 (2025). https://doi.org/10.1038/s41928-025-01447-6

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue date:

  • DOI: https://doi.org/10.1038/s41928-025-01447-6

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing