spore: profile
id: silicon
spore_version: 0.2
family: semiconductor-materials
name: Silicon
abbreviation: Si
role: semiconductor
category: semiconductors
type: silicon
summary: |
  Silicon is the element Si, used as single-crystal wafers for chips and as the base material of most solar cells. The sources read for this profile give a density of 2.328 g/cm3, a band gap of 1.12 eV at 300 K, a melting point of 1415 °C and a relative permittivity of 11.9 at 300 K. Its electrical behaviour depends strongly on doping: a supplier table gives CZ boron-doped wafers a resistivity range of 0.001 to 50 Ω·cm.
best_for: 'Semiconductor wafers: a 1.12 eV band gap at 300 K and a well-documented resistivity range from doping'
weakest_at: 'Light emission and heat flow: an indirect band gap (not stated in the sources read) and thermal conductivity of 150 W/(m·K), well below metals'
identity:
  formula: Si, elemental silicon, supplied as single-crystal wafers grown by Czochralski (CZ) or float-zone (FZ) methods
  source: pveducation
  where: Atomic weight row and Section 9 Material Properties (atomic weight printed as 28.09)
tags:
  environments: []
  stresses: []
  applications:
    - electronics-and-chips
    - solar-arrays
properties:
  - benchmark: density
    label: Density
    value: 2.328
    unit: g/cm3
    scope: material
    conditions:
      temperature: not stated on the page
    method: Value printed in a materials property table
    status: ground
    source: pveducation
    where: Section 9 Material Properties, row Density (ρ)
  - benchmark: lattice_constant
    label: Lattice constant
    value: 0.543095
    unit: nm
    scope: material
    conditions:
      temperature: not stated on the page
    method: Value printed in a materials property table
    status: ground
    source: pveducation
    where: Section 9 Material Properties, row Lattice constant
  - benchmark: bandgap
    label: Energy band gap (table at 300 K)
    value: 1.12
    unit: eV
    scope: material
    conditions:
      temperature: 300 K (table title)
    method: Value printed in a materials property table
    status: ground
    source: eesemi
    where: Table Properties of Silicon (Si), Germanium (Ge), and Gallium Arsenide (GaAs) at 300 deg K, row Energy Gap at 300K
  - benchmark: bandgap
    label: Energy band gap (no temperature stated)
    value: 1.1242
    unit: eV
    scope: material
    conditions:
      temperature: not stated on the page
    method: Value printed in a materials property table
    status: ground
    source: pveducation
    where: Section 9 Material Properties, row Energy bandgap (EG)
  - benchmark: intrinsic_carrier_concentration
    label: Intrinsic carrier concentration (300 K table)
    value: 14500000000
    unit: cm-3
    scope: material
    conditions:
      temperature: 300 K (table title)
    method: Value printed in a materials property table
    status: ground
    source: eesemi
    where: Table at 300 deg K, row Intrinsic Carrier Concentration
  - benchmark: intrinsic_carrier_concentration
    label: Intrinsic carrier concentration (updated values)
    value: 10000000000
    unit: cm-3
    scope: material
    conditions:
      temperature: 300 K
      basis: 'footnote: updated values from Sproul, Green and Zhao (1990) and Sproul and Green (1991)'
    method: Value printed in a materials property table
    status: ground
    source: pveducation
    where: Section 9 Material Properties, row Intrinsic carrier concentration (ni) at 300K
  - benchmark: electron_mobility
    label: Electron drift mobility
    value: 1500
    unit: cm2/(V·s)
    scope: material
    conditions:
      temperature: 300 K (table title)
      type: drift mobility, doping not stated
    method: Value printed in a materials property table
    status: ground
    source: eesemi
    where: Table at 300 deg K, row Mobility (Drift), electrons
  - benchmark: hole_mobility
    label: Hole drift mobility
    value: 475
    unit: cm2/(V·s)
    scope: material
    conditions:
      temperature: 300 K (table title)
      type: drift mobility, doping not stated
    method: Value printed in a materials property table
    status: ground
    source: eesemi
    where: Table at 300 deg K, row Mobility (Drift), holes
  - benchmark: intrinsic_resistivity
    label: Intrinsic resistivity
    value: 230000
    unit: Ω·cm
    scope: material
    conditions:
      temperature: 300 K (table title)
      doping: intrinsic, undoped
    method: Value printed in a materials property table
    status: ground
    source: eesemi
    where: Table at 300 deg K, row Intrinsic Resistivity (printed as 2.3 x 10^5)
  - benchmark: relative_permittivity
    label: Relative permittivity
    value: 11.7
    unit: dimensionless
    scope: material
    conditions:
      temperature: not stated on the page
    method: Value printed in a materials property table
    status: ground
    source: pveducation
    where: Section 9 Material Properties, row Relative permittivity (εr)
  - benchmark: relative_permittivity
    label: Dielectric constant (300 K table)
    value: 11.9
    unit: dimensionless
    scope: material
    conditions:
      temperature: 300 K (table title)
    method: Value printed in a materials property table
    status: ground
    source: eesemi
    where: Table at 300 deg K, row Dielectric Constant (no unit printed)
  - benchmark: melting_point
    label: Melting point
    value: 1415
    unit: °C
    scope: material
    conditions:
      basis: melting point as printed, no pressure or purity stated
    method: Value printed in a materials property table
    status: ground
    source: pveducation
    where: Section 9 Material Properties, row Melting point
  - benchmark: thermal_conductivity
    label: Thermal conductivity
    value: 150
    unit: W/(m·K)
    scope: material
    conditions:
      temperature: not stated on the page
    method: Value printed in a materials property table
    status: ground
    source: pveducation
    where: Section 9 Material Properties, row Thermal conductivity (printed as 1.5 W cm-1K-1 and 150 W m-1K-1)
  - benchmark: thermal_conductivity
    label: Thermal conductivity (300 K table)
    value: 1.5
    unit: W/(cm·°C)
    scope: material
    conditions:
      temperature: 300 K
    method: Value printed in a materials property table
    status: ground
    source: eesemi
    where: Table at 300 deg K, row Thermal Conductivity at 300 K
  - benchmark: effective_density_of_states
    label: Effective density of states, conduction band
    value: 30000000000000000000
    unit: cm-3
    scope: material
    conditions:
      temperature: not stated on the page
    method: Value printed in a materials property table
    status: ground
    source: pveducation
    where: Section 9 Material Properties, row NC
  - benchmark: effective_density_of_states
    label: Effective density of states, valence band
    value: 10000000000000000000
    unit: cm-3
    scope: material
    conditions:
      temperature: not stated on the page
    method: Value printed in a materials property table
    status: ground
    source: pveducation
    where: Section 9 Material Properties, row NV
  - benchmark: resistivity_range
    label: Resistivity range, CZ boron-doped (p-type) wafer
    value: 0.001
    value_high: 50
    unit: Ω·cm
    scope: material
    conditions:
      dopant: boron, p-type
      growth: Czochralski (CZ)
      temperature: not stated
    method: Supplier resistivity range for the grade
    status: ground
    source: elcat
    where: Dopant table, row Boron (p-type Si:B), CZ
  - benchmark: resistivity_range
    label: Resistivity range, CZ phosphorus-doped (n-type) wafer
    value: 1
    value_high: 50
    unit: Ω·cm
    scope: material
    conditions:
      dopant: phosphorus, n-type
      growth: Czochralski (CZ)
      temperature: not stated
    method: Supplier resistivity range for the grade
    status: ground
    source: elcat
    where: Dopant table, row Phosphorus (n-type Si:P), CZ
  - benchmark: resistivity_range
    label: Resistivity range, float-zone wafer
    value: 0.01
    value_high: 10000
    unit: Ω·cm
    scope: material
    conditions:
      growth: float-zone (FZ) and CFZ
      temperature: not stated
    method: Supplier resistivity range for the grade
    status: ground
    source: elcat
    where: Dopant table, FZ/CFZ rows for boron and phosphorus
  - benchmark: carbon_concentration
    label: Carbon concentration, CZ silicon
    value: 0.5
    unit: ppma
    scope: material
    conditions:
      growth: Czochralski (CZ)
      limit: maximum
    method: Supplier specification
    status: ground
    source: elcat
    where: Carbon concentration row, CZ silicon
  - benchmark: oxygen_concentration
    label: Oxygen concentration, CZ silicon
    value: 24
    value_high: 38
    unit: ppma
    scope: material
    conditions:
      growth: Czochralski (CZ)
      standard: ASTM F121-76
    method: Supplier specification, standard grade
    status: ground
    source: elcat
    where: Oxygen concentration row, CZ silicon
corrosion:
  - environment: Ambient air, room temperature
    headline: Silicon forms a thin native oxide in air at room temperature.
    effect: A 2013 J. Phys. Chem. C paper on oxidation of silicon gives a native oxide about 10 Å (1 nm) thick and calls it a poor dielectric, so it is usually removed before oxidation for microelectronics.
    rating: low
    conditions:
      basis: Thickness from the paper; the low rating is the assistant's reading of a thin oxide, not a printed rating
    source: khalilov-jpcc-2013
    where: Abstract (native oxide thickness about 10 Å); Introduction, paragraph 2 (up to 1 nm, poor dielectric)
risks:
  hazards:
    - text: PubChem aggregates GHS reports for silicon from 3,263 company reports. Most reports (3,142) say it does not meet GHS hazard criteria. The rest give H228 (flammable solid) and H320 (causes eye irritation), signal word Danger.
      ghs:
        - 'H228: Flammable solid'
        - 'H320: Causes eye irritation'
      source: pubchem-si
      where: Safety and Hazards, GHS Classification (CID 5461123)
    - text: Precautionary statements listed with the GHS entry include P210 (keep away from heat, sparks and open flames), P280 (protective gloves) and P305+P351+P338 (eye rinsing).
      ghs: []
      source: pubchem-si
      where: Safety and Hazards, GHS Classification precautionary statements
  failure_risks:
    - source: elcat
      where: Dopant table, rows for boron and phosphorus, CZ
      mode: 'Wafer grade mismatch: a supplier gives CZ boron-doped wafers a resistivity range'
      consequence: 'Wafer grade mismatch: a supplier gives CZ boron-doped wafers a resistivity range of 0.001 to 50 Ω·cm, so the wrong dopant or growth method changes the device behaviour.'
  side_effects: []
  handling:
    - text: Keep away from heat, sparks and open flames, as the PubChem GHS entry for the flammable-solid class advises. The entry is an aggregate and applies to the form handled; check the supplier SDS for wafer or powder.
      source: pubchem-si
      where: Safety and Hazards, precautionary statements P210
  mitigations: []
uses:
  - application: electronics-and-chips
    device: Single-crystal silicon wafer substrate
    example: Wafers grown by Czochralski or float-zone methods, sold by resistivity grade
    source: elcat
    where: Wafer specification page, product range
  - application: electronics-and-chips
    device: Semiconductor chips
    example: Silicon metal is further processed into semiconductor-grade polysilicon for chips; the LMU review says CZ single crystal is the raw material for microelectronics
    source: usgs-si-2026
    where: Domestic Production and Use paragraph; LMU review, introduction
  - application: solar-arrays
    device: Silicon solar cell
    example: NASA reports that Si solar cells are the most important case in its displacement-damage analysis, which models proton damage to cells
    source: nasa-tp-2004-213338
    where: Section 9, Quantifying low energy proton effects
supply:
  - subject: Silicon metal and silicon materials (feedstock for chips, solar-grade polysilicon, aluminium alloys and silicones)
    abundance: World and domestic resources are abundant; the source of silicon is silica (quartzite).
    producers:
      - country: China
        share_percent: 87
        year: 2025
        basis: 'computed: 4,000 kt of 4,600 kt world silicon metal (USGS table, World Production)'
      - country: Brazil
        share_percent: 3.9
        year: 2025
        basis: 'computed: 180 kt of 4,600 kt'
      - country: Norway
        share_percent: 2.8
        year: 2025
        basis: 'computed: 130 kt of 4,600 kt'
    us_position: 'US silicon metal imports were an estimated 180 kt in 2025, against 117 kt in 2024. Total net import reliance for ferrosilicon and silicon metal was above 50 % in 2025e. Silicon metal imports 2021 to 2024: Brazil 38 %, Canada 29 %, Norway 12 %.'
    source: usgs-si-2026
    where: Salient Statistics; Events, Trends, and Issues; Import Sources; World Production table
media: []
documents:
  - title: EL-CAT silicon data sheet (CZ and FZ specifications)
    type: datasheet
    url: https://www.el-cat.com/dscsi.htm
  - title: USGS Mineral Commodity Summaries 2026, Silicon
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silicon.pdf
  - title: PubChem record for silicon (CID 5461123), GHS classification and identifiers
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Silicon
  - title: NASA TP-2004-213338, Displacement Damage Effects in Solar Cells, Mining Damage
    type: report
    url: https://ntrs.nasa.gov/api/citations/20050071537/downloads/20050071537.pdf
  - title: Khalilov et al., New Mechanism for Oxidation of Native Silicon Oxide, J. Phys. Chem. C 2013
    type: paper
    url: https://medialibrary.uantwerpen.be/oldcontent/container2642/files/jpcc13newmechanisms.pdf
  - title: Single-Crystal Growth of Silicon (Czochralski process), LMU Munich
    type: paper
    url: https://www.cup.lmu.de/ac/kluefers/homepage/publ_pdf/czochralski_engl.pdf
gaps:
  - 'Indirect or direct band gap type: not stated in the sources read.'
  - 'Crystal structure and space group: pveducation says the crystal structure is not named on its page; no other source read.'
  - 'Electron and hole mobility at doping levels other than undoped: the pveducation mobility tables gave units only.'
  - 'Corrosion in acids or alkalis (HF, KOH etch): not read in this run.'
  - 'Float-zone process steps: not read in this run; only the CZ process is sourced.'
  - 'Radiation damage: the NASA report gives the method and says Si solar cells are the key case, but its numeric values are in figures that were not readable as text, so no radiation number is given.'
  - 'Crystal structure (diamond cubic): not confirmed on a fetched page in this run.'
  - 'Critical-mineral list status: the EU and USGS critical lists were not checked for silicon in this run.'
  - Intrinsic carrier concentration disagrees between sources (1.0e10 vs 1.45e10 cm-3 at 300 K); both are listed with their source.
  - NIST WebBook silicon page gave only an Antoine vapour-pressure equation; no property from it was used.
  - 'Only three sources were reached: ioffe.ru could not be fetched (TLS certificate error), and the Columbia lecture PDF and the microchemicals wafer PDF could not be read.'
sources:
  pveducation:
    title: PVEducation, General Properties of Silicon (Section 9, Material Properties)
    url: https://www.pveducation.org/pvcdrom/materials/general-properties-of-silicon
    kind: web
    license: page content, cited as published
  eesemi:
    title: EE Semi, Properties of Silicon (Si), Germanium (Ge), and Gallium Arsenide (GaAs) at 300 deg K
    url: https://www.eesemi.com/sigegaas.htm
    kind: web
    license: page content, cited as published
  elcat:
    title: EL-CAT, Silicon data sheet (CZ and FZ dopant, resistivity and specification tables)
    url: https://www.el-cat.com/dscsi.htm
    kind: datasheet
    license: page content, cited as published
  usgs-si-2026:
    title: USGS Mineral Commodity Summaries 2026, Silicon
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silicon.pdf
    kind: report
    license: public domain (USGS), cited as published
  pubchem-si:
    title: PubChem, Silicon (CID 5461123), GHS classification
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Silicon
    kind: database
    license: public domain (NCBI), cited as published
  nasa-tp-2004-213338:
    title: NASA/TP-2004-213338, Displacement Damage Effects in Solar Cells, Mining Damage (S.R. Messenger)
    url: https://ntrs.nasa.gov/api/citations/20050071537/downloads/20050071537.pdf
    kind: report
    license: public domain (NASA), cited as published
  khalilov-jpcc-2013:
    title: Khalilov et al., New Mechanism for Oxidation of Native Silicon Oxide, J. Phys. Chem. C 2013, 117, 9819-9825
    url: https://medialibrary.uantwerpen.be/oldcontent/container2642/files/jpcc13newmechanisms.pdf
    kind: paper
    license: author copy, cited as published
  lmu-cz-2008:
    title: Single-Crystal Growth of Silicon (Czochralski process), LMU Munich, English version
    url: https://www.cup.lmu.de/ac/kluefers/homepage/publ_pdf/czochralski_engl.pdf
    kind: paper
    license: author copy, cited as published
license: CC-BY-4.0
checked_values: 21
updated: '2026-10-19'
story:
  risk_groups:
    - title: For people
      lead: The PubChem aggregate for silicon is mostly "not classified" (3,142 of 3,263 reports). A minority of reports give H228 (flammable solid) and H320 (eye irritation). Low concern in the aggregate; check the supplier SDS for the form
      level: 1
      verdict: Low concern in the aggregate; check the supplier SDS for
      points:
        - label: Silicon as a substance
          line: PubChem's aggregate lists H228 and H320 from a small share of reports. No exposure limit was read in this run, so none is given here.
    - title: If it fails
      lead: Failure routes found in the sources are about the wafer grade, not about hazards.
      points:
        - label: Wrong resistivity
          line: A supplier gives CZ boron-doped wafers a resistivity range of 0.001 to 50 Ω·cm, so the grade has to be chosen for the device, or the wafer will not behave as intended.
        - label: Oxygen content
          line: CZ silicon carries oxygen in the range 24 to 38 ppma under ASTM F121-76, a value the supplier lists as standard.
    - title: Handling and storage
      points:
        - label: Keep to the grade
          line: Choose the growth method and dopant from the supplier table. The sources read here give no storage advice.
  recipe:
    line: 'Silicon is the element Si, atomic weight 28.085 (PubChem). Commercial single crystals are made by the Czochralski process: polysilicon is melted at just above its melting point in a silica crucible under 10 to 200 mbar of argon, a seed is dipped in and slowly pulled, and the crystal is grown to diameters up to 300 mm. The LMU review says about 95 % of world silicon single-crystal production uses this process.'
    parts:
      - name: Silicon
        symbol: Si
        share_percent: 100
        atomic_weight: 28.085
        role: Element. The crystal is pure silicon, doped with boron or phosphorus to set resistivity.
        source: pubchem-si
        where: Compound record, Molecular Weight (CID 5461123)
  why: Silicon is the semiconductor used for chips and, in the user brief, for solar cells. The sources read here give its density as 2.328 g/cm3, its band gap as 1.12 eV at 300 K, and its melting point as 1415 °C. Its electrical properties change with doping, which is why suppliers sell it as wafers across a wide resistivity range.
  uses:
    - where: Wafers
      line: Single-crystal silicon is sold as wafers grown by Czochralski or float-zone methods. The supplier table covers resistivity from 0.001 to 50 Ω·cm for CZ boron-doped grades, and from 0.01 to 10000 Ω·cm for float-zone grades.
  can_do:
    - label: Act as a semiconductor
      value: 1.12 eV
      benchmark: bandgap
      line: At 300 K the band gap is 1.12 eV in one table and 1.1242 eV in another, so the two sources agree to about one per cent.
    - label: Carry heat
      value: 150 W/(m·K)
      benchmark: thermal_conductivity
      line: The printed thermal conductivity is 150 W/(m·K) with no temperature stated, or 1.5 W/(cm·°C) at 300 K in a second table.
    - label: Weight
      value: 2.328 g/cm3
      benchmark: density
      line: Density is printed as 2.328 g/cm3.
  compare: Intrinsic silicon at 300 K has a resistivity of 230000 Ω·cm, while a CZ boron-doped grade can be as low as 0.001 Ω·cm. Doping changes the resistance by many orders of magnitude. The intrinsic carrier concentration is printed as 1.0e10 cm-3 in one source and 1.45e10 cm-3 in another, both at 300 K. Check which edition a design rule is based on.
  good_for:
    - 'label: Wafers with a set resistivity line: Doping sets the resistivity, and suppliers quote it as a range per dopant and growth method.'
  watch_out:
    - 'label: Mixed sources line: Some values carry no temperature, so compare only figures that state the same condition.'
    - 'label: Thermal conductivity line: At 150 W/(m·K) silicon conducts heat far less well than copper, a fact that matters for thermal control.'
  verdict: Silicon is a well-documented semiconductor. Its band gap, density and melting point are printed in more than one source, and its resistivity is set by doping. Its hazards are low in the PubChem aggregate. Radiation numbers and acid or alkali corrosion are not covered by the sources read here.
  handling:
    - Silicon wafers are made to a resistivity grade. Pick the dopant and growth method from the supplier table, and check the supplier SDS for the form handled.
  compare_rows:
    - scope: material
      label: Density
      benchmark: density
    - scope: material
      label: Melting point
      benchmark: melting_point
    - scope: material
      label: Thermal conductivity
      benchmark: thermal_conductivity