Electrical and thermal characterisation of liquid metal thin-film Ga2O3–SiO2 heterostructures

Alexander Petkov; Abhishek Mishra; Mattia Cattelan; Daniel Field; James W Pomeroy; Martin Kuball

doi:10.1038/s41598-023-30638-4

Electrical and thermal characterisation of liquid metal thin-film Ga₂O₃–SiO₂ heterostructures

Alexander Petkov, Abhishek Mishra, Mattia Cattelan, Daniel Field, James W Pomeroy, Martin Kuball^*

^*Corresponding author for this work

Research output: Contribution to journal › Article (Academic Journal) › peer-review

4 Citations (Scopus)

Abstract

Heterostructures of Ga2O3 with other materials such as Si, SiC or diamond, are a possible way of addressing the low thermal conductivity and lack of p-type doping of Ga2O3 for device applications, as well as of improving device reliability. In this work we study the electrical and thermal properties of Ga2O3–SiO2 heterostructures. Here, thin-film gallium oxide with thickness ranging between 8 and 30 nm was deposited onto a silicon substrate with a thermal oxide by means of oxidised liquid gallium layer delamination. The resulting heterostructure is then characterised by means of X-ray photoelectron spectroscopy and transient thermoreflectance. The thin-film gallium oxide valence band offset with respect to the SiO2 is measured as 0.1 eV and predicted as −2.3 eV with respect to diamond. The thin-film’s out-of-plane thermal conductivity is determined to be 3 ±0.5 Wm−1
K−1
, which is higher than what has been previously measured for other polycrystalline Ga2
O3
films of comparable thickness.

Original language	English
Article number	3437
Number of pages	7
Journal	Scientific Reports
Volume	13
Issue number	1
DOIs	https://doi.org/10.1038/s41598-023-30638-4
Publication status	Published - 1 Mar 2023

Bibliographical note

The authors acknowledge use of the University of Bristol cleanroon and NanoESCA facilities. AP acknowledges funding and support from the Engineering and Physical Sciences Research Council (EPSRC) Centre for Doctoral Training in Condensed Matter Physics (CDTCMP), Grant No. EP/L015544/1. The work of Martin Kuball was supported by the Royal Academy of Engineering through the Chair in Emerging Technologies Scheme. The authors also wish to thank Jude Lavrock for helpful discussion on XPS.

Research Groups and Themes

CDTR

Keywords

gallium oxide
thermal conductivity
semiconductors
ultra-wide band gap materials

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Cite this

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title = "Electrical and thermal characterisation of liquid metal thin-film Ga2O3–SiO2 heterostructures",

abstract = "Heterostructures of Ga2O3 with other materials such as Si, SiC or diamond, are a possible way of addressing the low thermal conductivity and lack of p-type doping of Ga2O3 for device applications, as well as of improving device reliability. In this work we study the electrical and thermal properties of Ga2O3–SiO2 heterostructures. Here, thin-film gallium oxide with thickness ranging between 8 and 30 nm was deposited onto a silicon substrate with a thermal oxide by means of oxidised liquid gallium layer delamination. The resulting heterostructure is then characterised by means of X-ray photoelectron spectroscopy and transient thermoreflectance. The thin-film gallium oxide valence band offset with respect to the SiO2 is measured as 0.1 eV and predicted as −2.3 eV with respect to diamond. The thin-film{\textquoteright}s out-of-plane thermal conductivity is determined to be 3 ±0.5 Wm−1 K−1, which is higher than what has been previously measured for other polycrystalline Ga2O3 films of comparable thickness.",

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author = "Alexander Petkov and Abhishek Mishra and Mattia Cattelan and Daniel Field and Pomeroy, {James W} and Martin Kuball",

note = "The authors acknowledge use of the University of Bristol cleanroon and NanoESCA facilities. AP acknowledges funding and support from the Engineering and Physical Sciences Research Council (EPSRC) Centre for Doctoral Training in Condensed Matter Physics (CDTCMP), Grant No. EP/L015544/1. The work of Martin Kuball was supported by the Royal Academy of Engineering through the Chair in Emerging Technologies Scheme. The authors also wish to thank Jude Lavrock for helpful discussion on XPS.",

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AU - Petkov, Alexander

AU - Mishra, Abhishek

AU - Cattelan, Mattia

AU - Field, Daniel

AU - Pomeroy, James W

AU - Kuball, Martin

N1 - The authors acknowledge use of the University of Bristol cleanroon and NanoESCA facilities. AP acknowledges funding and support from the Engineering and Physical Sciences Research Council (EPSRC) Centre for Doctoral Training in Condensed Matter Physics (CDTCMP), Grant No. EP/L015544/1. The work of Martin Kuball was supported by the Royal Academy of Engineering through the Chair in Emerging Technologies Scheme. The authors also wish to thank Jude Lavrock for helpful discussion on XPS.

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N2 - Heterostructures of Ga2O3 with other materials such as Si, SiC or diamond, are a possible way of addressing the low thermal conductivity and lack of p-type doping of Ga2O3 for device applications, as well as of improving device reliability. In this work we study the electrical and thermal properties of Ga2O3–SiO2 heterostructures. Here, thin-film gallium oxide with thickness ranging between 8 and 30 nm was deposited onto a silicon substrate with a thermal oxide by means of oxidised liquid gallium layer delamination. The resulting heterostructure is then characterised by means of X-ray photoelectron spectroscopy and transient thermoreflectance. The thin-film gallium oxide valence band offset with respect to the SiO2 is measured as 0.1 eV and predicted as −2.3 eV with respect to diamond. The thin-film’s out-of-plane thermal conductivity is determined to be 3 ±0.5 Wm−1 K−1, which is higher than what has been previously measured for other polycrystalline Ga2O3 films of comparable thickness.

AB - Heterostructures of Ga2O3 with other materials such as Si, SiC or diamond, are a possible way of addressing the low thermal conductivity and lack of p-type doping of Ga2O3 for device applications, as well as of improving device reliability. In this work we study the electrical and thermal properties of Ga2O3–SiO2 heterostructures. Here, thin-film gallium oxide with thickness ranging between 8 and 30 nm was deposited onto a silicon substrate with a thermal oxide by means of oxidised liquid gallium layer delamination. The resulting heterostructure is then characterised by means of X-ray photoelectron spectroscopy and transient thermoreflectance. The thin-film gallium oxide valence band offset with respect to the SiO2 is measured as 0.1 eV and predicted as −2.3 eV with respect to diamond. The thin-film’s out-of-plane thermal conductivity is determined to be 3 ±0.5 Wm−1 K−1, which is higher than what has been previously measured for other polycrystalline Ga2O3 films of comparable thickness.

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KW - thermal conductivity

KW - semiconductors

KW - ultra-wide band gap materials

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DO - 10.1038/s41598-023-30638-4

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