spore: profile
id: gallium-oxide
spore_version: 0.2
family: semiconductor-materials
name: Gallium oxide (beta-Ga2O3)
abbreviation: Ga2O3
role: ultra-wide-bandgap power semiconductor
category: semiconductors
type: ga2o3
summary: |
  Beta-gallium oxide (beta-Ga2O3) is an ultra-wide-bandgap semiconductor. The 2019 review in Journal of Semiconductors gives a band gap of 4.8 eV and an estimated critical (breakdown) field of 8 MV/cm for the beta phase. Its Table 1 gives a Baliga figure of merit of 3200 relative to silicon (Si = 1). Table 1 also gives a thermal conductivity of 10 to 30 W/mK. No radiation, space or corrosion test of this material was read in this run.
best_for: Power switching devices where a wide band gap of 4.8 eV and an estimated breakdown field of 8 MV/cm matter (per the 2019 review)
weakest_at: Thermal conductivity of 10 to 30 W/mK (Table 1 of the 2019 review, temperature not stated), and no space or radiation data in the sources read here
identity:
  formula: Ga2O3 (beta polymorph of gallium(III) oxide, two gallium atoms and three oxygen atoms per formula unit)
  cas: 12024-21-4
  source: wiki-ga2o3
  where: Identifiers box of the Wikipedia article (CAS number only; no other identifiers taken from it)
tags:
  environments: []
  stresses: []
  applications:
    - electronics-and-chips
properties:
  - benchmark: band_gap
    label: Band gap, beta-Ga2O3
    value: 4.8
    unit: eV
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      temperature: not stated
    method: Value printed in Table 1 of an open-access review of gallium oxide power devices
    status: ground
    note: The abstract of the same review gives a range of 4.5 to 4.8 eV, so the value depends on the source.
    source: jos-ga2o3-review
    where: Table 1 (material parameters), row Bandgap
  - benchmark: breakdown_field
    label: Critical (breakdown) electric field, beta-Ga2O3
    value: 8
    unit: MV/cm
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      basis: described as estimated in the abstract; no test condition given
    method: Estimated value printed in the abstract and in Table 1 of the review; not a measured breakdown test
    status: ground
    source: jos-ga2o3-review
    where: Abstract; Table 1, row Critical field (EC)
  - benchmark: electron_mobility
    label: Intrinsic electron mobility limit, beta-Ga2O3
    value: 250
    unit: cm2/(V·s)
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      basis: intrinsic limit, as printed in the abstract
    method: Value printed in the abstract of the review
    status: ground
    note: Table 1 of the same review gives a carrier mobility of 300 cm2/(V·s), so the abstract and table disagree. Both values are kept.
    source: jos-ga2o3-review
    where: Abstract
  - benchmark: electron_mobility
    label: Carrier mobility, beta-Ga2O3
    value: 300
    unit: cm2/(V·s)
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      temperature: not stated
    method: Value printed in Table 1 of the review
    status: ground
    note: The abstract gives an intrinsic limit of 250 cm2/(V·s), which differs from this table value.
    source: jos-ga2o3-review
    where: Table 1 (material parameters), row Carrier mobility
  - benchmark: dielectric_constant
    value: 11
    unit: '-'
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      temperature: not stated
    method: Value printed in Table 1 of the review (dimensionless)
    status: ground
    source: jos-ga2o3-review
    where: Table 1 (material parameters), row Dielectric constant
  - benchmark: thermal_conductivity
    label: Thermal conductivity, beta-Ga2O3 (range)
    value: 10
    value_high: 30
    bound: range
    unit: W/mK
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      temperature: not stated
    method: Range printed in Table 1 of the review
    status: ground
    source: jos-ga2o3-review
    where: Table 1 (material parameters), row Thermal conductivity
  - benchmark: saturation_velocity
    label: Saturation velocity, beta-Ga2O3
    value: 2
    unit: 10^7 cm/s
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      temperature: not stated
    method: Value printed in Table 1 of the review, in the unit the table prints
    status: ground
    source: jos-ga2o3-review
    where: Table 1 (material parameters), row Saturation velocity (vsat)
  - benchmark: baliga_figure_of_merit
    label: Baliga figure of merit relative to silicon
    value: 3200
    unit: '-'
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      basis: ratio to silicon, where silicon equals 1; not an absolute figure
      temperature: not stated
    method: Ratio printed in Table 1 of the review
    status: ground
    note: The abstract describes this figure of merit as more than 3000 relative to silicon, which is consistent with the table value.
    source: jos-ga2o3-review
    where: Table 1 (material parameters), row Baliga FOM (epsilon mu Ec^3), relative to Si
  - benchmark: density
    label: Relative density, gallium(III) oxide powder
    value: 5.88
    unit: g/mL
    scope: material
    conditions:
      form: powder, white (Aldrich product 215066)
      temperature: 25 °C
    method: Relative density printed in Section 9.1 of the supplier SDS; a supplier value for the powder, not a crystal measurement
    status: ground
    note: The SDS gives 5.88 g/mL for the powder. No density for a single beta-Ga2O3 crystal is printed in any source read in this run.
    source: aldrich-215066-sds
    where: Section 9.1 (physical and chemical properties), item m, relative density
  - benchmark: johnson_figure_of_merit
    label: Johnson figure of merit relative to silicon, beta-Ga2O3
    value: 2844
    unit: '-'
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      basis: ratio to silicon, where silicon equals 1
      temperature: not stated
    method: Ratio printed in Table 1 of the review, Johnson FOM row
    status: ground
    source: jos-ga2o3-review
    where: Table 1, FOM relative to Si section, row Johnson FOM
  - benchmark: baliga_high_frequency_figure_of_merit
    label: Baliga high-frequency figure of merit relative to silicon, beta-Ga2O3
    value: 142
    unit: '-'
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      basis: ratio to silicon, where silicon equals 1
      temperature: not stated
    method: Ratio printed in Table 1 of the review, Baliga High Frequency FOM row
    status: ground
    source: jos-ga2o3-review
    where: Table 1, FOM relative to Si section, row Baliga High Frequency FOM
  - benchmark: keyes_figure_of_merit
    label: Keyes figure of merit relative to silicon, beta-Ga2O3
    value: 0.2
    unit: '-'
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      basis: ratio to silicon, where silicon equals 1
      temperature: not stated
    method: Ratio printed in Table 1 of the review, Keyes FOM row
    status: ground
    source: jos-ga2o3-review
    where: Table 1, FOM relative to Si section, row Keyes FOM
  - benchmark: thermal_conductivity
    label: Thermal conductivity, beta-Ga2O3 along [100], room temperature
    value: 10.9
    unit: W/mK
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      direction: '[100]'
      temperature: room temperature
    method: Time-domain thermoreflectance on single crystals; value printed in the abstract
    status: ground
    note: Printed as 10.9 ± 1.0 W/mK. The ± 1.0 is the uncertainty the paper prints.
    source: guo-2014-tc
    where: Abstract
  - benchmark: thermal_conductivity
    label: Thermal conductivity, beta-Ga2O3 along [010], room temperature
    value: 27
    unit: W/mK
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      direction: '[010]'
      temperature: room temperature
    method: Time-domain thermoreflectance on single crystals; value printed in the abstract
    status: ground
    note: Printed as 27.0 ± 2.0 W/mK. The ± 2.0 is the uncertainty the paper prints.
    source: guo-2014-tc
    where: Abstract
  - benchmark: thermal_conductivity
    label: Thermal conductivity, beta-Ga2O3 along [100], room temperature, 3 omega method
    value: 13
    unit: W/mK
    scope: material
    conditions:
      polymorph: beta-Ga2O3
      direction: '[100]'
      temperature: room temperature
      crystal: Czochralski-grown bulk crystals, Mg-doped and undoped
    method: Electrical 3 omega method on bulk crystals; value printed in the abstract
    status: ground
    note: Printed as 13 ± 1 W/mK, the uncertainty the paper prints. It is a second method on a different crystal set from the TDTR values above.
    source: handwerg-2014-tc
    where: Abstract
uses:
  - application: electronics-and-chips
    device: Field-plated MOSFET (research device in the review)
    example: The review reports a field-plated MOSFET with a breakdown voltage of 1850 V (Fig. 11).
    source: jos-ga2o3-review
    where: Figure 11 caption
  - application: electronics-and-chips
    device: GOOI FET (research device in the review)
    example: The review reports GOOI FETs with an on/off ratio of 10^10 and a maximum drain current of 1.5 A/mm in depletion mode and 1.0 A/mm in enhancement mode (Fig. 21).
    source: jos-ga2o3-review
    where: Figure 21 caption
risks:
  hazards:
    - text: 'Aldrich supplier SDS for gallium(III) oxide, product 215066 (Version 4.3): Sections 2.1 and 2.2 read ''Not a hazardous substance or mixture.'' with no GHS label elements.'
      ghs: []
      source: aldrich-215066-sds
      where: Sections 2.1 and 2.2
    - text: ChemicalBook supplier SDS for CAS 12024-21-4 (revision date printed 2026-08-15) prints the hazard statements H315 (causes skin irritation), H319 (causes serious eye irritation) and H335 (may cause respiratory irritation), with the signal word Warning and precautionary statements P261, P271 and P280. This conflicts with the Aldrich SDS, so both are kept.
      ghs:
        - H315
        - H319
        - H335
      source: chemicalbook-ga2o3-sds
      where: GHS hazard statements and precautionary statements block
  failure_risks:
    - mode: Reaction with strong oxidizing agents
      trigger: Contact with strong oxidizing agents, which the Aldrich SDS lists as incompatible
      consequence: 'The SDS gives no reaction products or rates: reactivity and hazardous reactions are ''no data available''.'
      source: aldrich-215066-sds
      where: Sections 10.1, 10.3 and 10.5
    - mode: Fire
      trigger: Exposure to a fire
      consequence: The SDS says the product does not burn and lists gallium oxides as the special fire hazard. Flash point is 'not applicable'.
      source: aldrich-215066-sds
      where: Sections 3.1, 5.2, 5.4 and 9.1 (flash point)
  handling:
    - text: 'Aldrich SDS: provide exhaust ventilation where dust forms, avoid dust formation, keep the container tightly closed in a dry and well-ventilated place, and do not let the product enter drains. Wear gloves and eye protection.'
      source: aldrich-215066-sds
      where: Sections 6.1, 6.2, 7.1, 7.2 and 8.2
supply:
  - subject: Gallium (the metal from which Ga2O3 is made)
    abundance: Average gallium content of bauxite is 50 parts per million (USGS, World Resources)
    producers:
      - country: China
        share_percent: 99
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals (described as used in semiconductors; no strategic designation printed)
        listed: true
      - list: EU critical raw materials list (Regulation (EU) 2024/1252, fifth list of 34 critical raw materials)
        listed: true
    recycling: 'USGS: old scrap none. Substantial new scrap from GaAs device manufacture is reprocessed to recover high-purity gallium at one facility in New York.'
    source: usgs-mcs2026-gallium
    where: Gallium chapter, Events, Trends, and Issues (China 99% of primary low-purity gallium production); World Resources (bauxite content); Recycling. The year for the 99% share is not printed in that sentence; 2025 is the year of the chapter's own production table.
documents:
  - title: A review of the most recent progresses of state-of-art gallium oxide power devices (Journal of Semiconductors 40(1), 011803)
    type: paper
    url: https://www.jos.ac.cn/en/article/doi/10.1088/1674-4926/40/1/011803
    year: 2019
  - title: 'USGS Mineral Commodity Summaries 2026: Gallium'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-gallium.pdf
    year: 2026
  - title: Safety Data Sheet, Gallium(III) oxide, Aldrich product 215066 (Version 4.3)
    type: sds
    url: https://www.physics.purdue.edu/primelab/safety/MSDS/SDS/gallium%20(III)%20oxide%20%20-%20Aldrich.pdf
    year: 2014
  - title: Chemical Safety Data Sheet MSDS / SDS, gallium(III) oxide (ChemicalBook)
    type: sds
    url: https://www.chemicalbook.com/msds/galliumiiioxide.htm
    year: 2026
  - title: Anisotropic Thermal Conductivity in Single Crystal beta-Gallium Oxide (arXiv:1412.7472)
    type: paper
    url: https://arxiv.org/abs/1412.7472
    year: 2014
  - title: Temperature-dependent thermal conductivity in Mg-doped and undoped beta-Ga2O3 bulk-crystals (arXiv:1407.4272)
    type: paper
    url: https://arxiv.org/abs/1407.4272
    year: 2014
gaps:
  - No oxidation, corrosion or ageing rate for beta-Ga2O3 was found in a source read in this run. The review covers material parameters and devices only. The Aldrich SDS gives only the incompatibility with strong oxidizing agents and storage stability ('Stable under recommended storage conditions').
  - No radiation, vacuum, atomic-oxygen or flight result was found. The Wikipedia article says the material is 'thought to be radiation-hard' but gives no numbers, so nothing is taken from it.
  - Melting point is not printed in any source read in this run. The Aldrich SDS says 'no data available' and the 2024 IJMMM review page prints no value. The Wikipedia infobox prints a melting point of 1,725 °C from a handbook, but Wikipedia is used here for composition only, so it is not entered. Density of a single crystal is not found; the only density entered is the supplier SDS relative density of the powder.
  - Crystal structure (monoclinic, space group C2/m) is on Wikipedia only and is left out under the composition-only rule for that source.
  - 'PubChem returned a reCAPTCHA page and American Elements returned HTTP 403, so no PubChem GHS record was read. The two supplier SDS sources read disagree on classification (Aldrich: not hazardous; ChemicalBook: H315, H319, H335). Both are kept.'
  - Supply shares are for gallium metal from the USGS chapter. No country share for gallium oxide itself was found.
  - Test temperatures for the band gap, mobility, dielectric constant and thermal conductivity are not stated in the review.
  - Band gap, breakdown field, electron mobility, saturation velocity and Baliga figure of merit are not in property-canon.yaml. They were added as snake_case names (band_gap, breakdown_field, electron_mobility, saturation_velocity, baliga_figure_of_merit). The Johnson, Baliga high-frequency and Keyes figures of merit were added the same way (johnson_figure_of_merit, baliga_high_frequency_figure_of_merit, keyes_figure_of_merit).
  - 'A second source for the band gap, mobility or breakdown field could not be read: the web search budget for this turn ran out, so only the 2019 review and the Wikipedia identifiers were used.'
sources:
  jos-ga2o3-review:
    title: A review of the most recent progresses of state-of-art gallium oxide power devices
    id: doi:10.1088/1674-4926/40/1/011803 (Journal of Semiconductors 40(1), 011803; authors Hong Zhou et al.)
    url: https://www.jos.ac.cn/en/article/doi/10.1088/1674-4926/40/1/011803
    year: 2019
    kind: paper
    license: not stated on the page read
  wiki-ga2o3:
    title: Gallium(III) oxide (Wikipedia, identifiers box)
    id: CAS 12024-21-4
    url: https://en.wikipedia.org/wiki/Gallium(III)_oxide
    year: 2026
    kind: web
    license: CC BY-SA (Wikipedia)
  usgs-mcs2026-gallium:
    title: Mineral Commodity Summaries 2026, Gallium
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-gallium.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-crit2025:
    title: About the 2025 List of Critical Minerals (USGS, final list of 60 minerals)
    id: Final 2025 List of Critical Minerals, November 2025
    url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals
    year: 2025
    kind: web
    license: public domain (USGS)
  ec-crm:
    title: Critical raw materials (European Commission, list of 34 critical raw materials under Regulation (EU) 2024/1252)
    id: Regulation (EU) 2024/1252
    url: https://single-market-economy.ec.europa.eu/sectors/raw-materials/areas-specific-interest/critical-raw-materials_en
    year: 2024
    kind: web
    license: European Commission web page
  aldrich-215066-sds:
    title: Safety Data Sheet, Gallium(III) oxide, Aldrich product 215066 (Version 4.3)
    id: Aldrich 215066, CAS 12024-21-4; revision date 06/25/2014, print date 01/15/2016 (as printed)
    url: https://www.physics.purdue.edu/primelab/safety/MSDS/SDS/gallium%20(III)%20oxide%20%20-%20Aldrich.pdf
    year: 2014
    kind: datasheet
    license: not stated on the document
  chemicalbook-ga2o3-sds:
    title: Chemical Safety Data Sheet MSDS / SDS, gallium(III) oxide (ChemicalBook)
    id: CAS 12024-21-4; revision date 2026-08-15 (as printed)
    url: https://www.chemicalbook.com/msds/galliumiiioxide.htm
    year: 2026
    kind: datasheet
    license: not stated on the page read
  guo-2014-tc:
    title: Anisotropic Thermal Conductivity in Single Crystal beta-Gallium Oxide (Guo et al.)
    id: arXiv:1412.7472
    url: https://arxiv.org/abs/1412.7472
    year: 2014
    kind: paper
    license: arXiv (see the paper page)
  handwerg-2014-tc:
    title: Temperature-dependent thermal conductivity in Mg-doped and undoped beta-Ga2O3 bulk-crystals (Handwerg et al.)
    id: arXiv:1407.4272
    url: https://arxiv.org/abs/1407.4272
    year: 2014
    kind: paper
    license: arXiv (see the paper page)
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 15
  unreachable: 4
  caveats: 3
  note: Written by an AI assistant on 2026-11-01 and deepened the same day from pages read in this run. Eight property values come from the 2019 review; the density comes from a supplier SDS, and two thermal conductivity values come from arXiv:1412.7472 and one from arXiv:1407.4272. PubChem (reCAPTCHA page), American Elements (HTTP 403), MDPI and NSF PAR (blocked) could not be read. Values have not been re-checked by a second reader.
story:
  recipe:
    line: Beta-Ga2O3 is gallium(III) oxide, a compound of two gallium atoms and three oxygen atoms. The 2019 review names the stable form beta-Ga2O3.
    parts:
      - name: Gallium
        symbol: Ga
        role: The metal cation in the oxide. The review gives no process route for the Ga2O3 crystal, so none is described here.
      - name: Oxygen
        symbol: O
        role: Bonded to the gallium atoms in the oxide lattice. Oxygen content sets the stoichiometry of the compound.
  risk_groups:
    - title: For people
      verdict: Sources conflict
      lead: Two supplier safety data sheets for gallium(III) oxide disagree. The Aldrich sheet (product 215066) lists no classification, and the ChemicalBook sheet prints the hazard statements H315, H319 and H335.
      points:
        - label: Check the supplier sheet
          line: PubChem returned a reCAPTCHA page and American Elements returned an access error. Check the safety data sheet for the lot you handle before handling powder or wafers.
  why: Beta-gallium oxide (beta-Ga2O3) is an ultra-wide-bandgap semiconductor. The 2019 review in Journal of Semiconductors gives a band gap of 4.8 eV and an estimated breakdown field of 8 MV/cm. Its Baliga figure of merit is printed as 3200 relative to silicon, which the review uses as a guide to power-device performance. The review also notes that melt-grown substrates could be lower cost. No space or radiation test is taken from the sources read here.
  uses:
    - where: Power transistors (research devices)
      line: The review reports a field-plated MOSFET with a breakdown voltage of 1850 V, and GOOI FETs with an on/off ratio of 10^10. These are laboratory devices described in the review, not commercial parts.
  can_do:
    - label: Band gap
      benchmark: band_gap
      value: 4.8 eV
      line: The review gives a band gap of 4.8 eV in Table 1. The abstract gives a range of 4.5 to 4.8 eV.
    - label: Electron mobility
      benchmark: electron_mobility
      value: 300 cm2/(V·s)
      line: The review gives a carrier mobility of 300 cm2/(V·s) in Table 1. The abstract gives an intrinsic limit of 250 cm2/(V·s).
    - label: Thermal conductivity
      benchmark: thermal_conductivity
      value: 10 to 30 W/mK
      line: Table 1 of the review gives a thermal conductivity of 10 to 30 W/mK, with no test temperature stated.
  compare: Table 1 of the review also prints values for silicon, GaAs, 4H-SiC, GaN and diamond. Only the beta-Ga2O3 column is entered in this profile. The Baliga figure of merit relative to silicon is 3200 in Table 1 and more than 3000 in the abstract.
  compare_rows:
    - label: Band gap
      benchmark: band_gap
    - label: Electron mobility
      benchmark: electron_mobility
    - label: Thermal conductivity
      benchmark: thermal_conductivity
  handling:
    - 'Aldrich SDS (product 215066): provide exhaust ventilation where dust forms, avoid dust formation, keep the container tightly closed in a dry and well-ventilated place, and do not let the product enter drains. The SDS is an older version, so check the current sheet for the lot you have.'
  good_for:
    - Power switching where a 4.8 eV band gap and an estimated 8 MV/cm breakdown field matter, per the 2019 review.
    - Power device research where the review's Baliga figure of merit, 3200 relative to silicon, is the target.
  watch_out:
    - Thermal conductivity of 10 to 30 W/mK in Table 1, with no test temperature stated.
    - The review's abstract and Table 1 disagree on electron mobility, 250 against 300 cm2/(V·s).
    - Most device figures in the review are for laboratory devices, not production parts.
  verdict: Beta-Ga2O3 has a wide band gap of 4.8 eV and an estimated breakdown field of 8 MV/cm in the 2019 review. This profile has no corrosion, radiation or space data, so no space verdict is possible from it.