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Overview

General comment

Not stated

Technology
Alkyl exchange reaction between gallium trichloride and trimethylaluminum
Geography
Global

System boundary

System boundary - Trimethylgallium (Ga(CH3)3)System boundary figure: identity, gate in, entering flows, the dashed system boundary and the unit processes inside it, the reference product, emissions and waste, and below it the flows that are recorded but not quantified. No inventory quantities.Trimethylgallium (Ga(CH3)3)DECLARED BOUNDARYGate-to-gate TMGa synthesis from GaCl3 +TMAlENTERING FLOWSElectricityWaterProcess gasesMaterialsSYSTEM BOUNDARYAGGREGATED PRODUCTION MODELModelled as one production operation.This dataset models the production of this material as a single aggregated operation at the supplier plant.Its inputs and outputs are recorded against that operation rather than a step-by-step recipe.REFERENCE PRODUCTTrimethylgalliumNot stated in the dataset recordEMISSIONS AND WASTEEmissions to airEmissions to waterWaste routesRECORDED BUT NOT QUANTIFIEDExclusions not yet characterisedNo exclusion record was found for this datasetNOT CHARACTERISEDsystem boundaryreference flowentering flowemission / waste

The figure groups this dataset's unit processes by class. It is not a count of manufacturing steps — each process runs over as many passes as the flow requires, and those pass counts ship with the dataset.

Download this figure (SVG)

Data quality and references

Composite DQI 1.7 Very good
Reliability
2.0
Completeness
1.0
Temporal
1.0
Geographic
2.0
Technological
4.0

Pedigree scores follow the ecoinvent data-quality matrix: 1 is the best attainable, 5 the weakest. The composite is their aggregate.

Sampling procedure
Production and high-purity patents for the alkyl-exchange route, a peer-reviewed life cycle study of III-V precursors for energy demand, a public critical-raw-material factsheet for gallium, and stoichiometric calculation over the stated reaction
Coverage status
Partial
Pedigree-scored source files
Not stated
Dataset sources
  • US Patent 20060075959A1 - Method for producing trimethylgallium
  • JP Patent 4784729B2 - Production of high purity TMGa
  • Smith, B.L., Babbitt, C.W., Horowitz, K., Gaustad, G., Hubbard, S.M. (2018). "Life Cycle Assessment of III-V Precursors for Photovoltaic and Semiconductor Applications." MRS Advances 3(25), 1399-1404. doi:10.1557/adv.2018.287
  • Factsheets on Critical Raw Materials (SCRREEN2 project): Gallium
  • Stoichiometric calculation

Technosphere inputs

8 flows. Quantities are not published; they ship with the dataset on Circa.

Gallium trichloride Materialkg · -10% / +11.8%
Derivation basis
  • The model specifies this input from the production route, either from the chemistry of the reaction or from the allowance the route sets for it. It also states the excess the route uses and the share it recovers for reuse.

The sources for this row are listed below.

Source citations (dataset-level)
Background data
proxy-mapped
Background dataset
gallium, high-grade
Notes
Made from Ga metal + HCl or Cl2
Uncertainty
-10% / +11.8% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit
kg
Trimethylaluminum Materialkg · -10% / +19.6%
Derivation basis
  • Quantity from the formulation/production-route recipe; upstream life cycle provenance is carried by the linked upstream unit process (see the technosphere reference)

The sources for this row are listed below.

Source citations (dataset-level)
Upstream REEL dataset
Trimethylaluminum (Al(CH3)3)
Background dataset
Modelled by REEL; see the upstream dataset above.
Notes
Excess ensures complete alkylation
Uncertainty
-10% / +19.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit
kg
Solvent (mesitylene or squalane) Materialkg · ±25%
Derivation basis
  • The model specifies this input from the production route, either from the chemistry of the reaction or from the allowance the route sets for it. It also states the excess the route uses and the share it recovers for reuse.

The sources for this row are listed below.

Source citations (dataset-level)
Background data
proxy-mapped
Background dataset
xylene, mixed
Notes
High-boiling hydrocarbon reaction medium, recovered between batches. This row is the non-recoverable make-up, which is what the process consumes.
Uncertainty
±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit
kg
Potassium fluoride (optional) Materialkg · ±100%
Derivation basis
  • The model specifies this input from the production route, either from the chemistry of the reaction or from the allowance the route sets for it. It also states the excess the route uses and the share it recovers for reuse.

The sources for this row are listed below.

Source citations (dataset-level)
Background data
proxy-mapped
Background dataset
sodium fluoride
Notes
Complexing agent for adduct purification to 6N purity
Uncertainty
±100% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit
kg
Electricity, Global (GLO) ElectricitykWh · ±27.3%
Source citations
Background data
ecoinvent 3.12
Background dataset
electricity, medium voltage
Notes
Heating, distillation, purification
Uncertainty
±27.3% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit
kWh
Fresh water WaterL · -33.3% / +66.7%
Derivation basis
  • Water demand specified by the model.

No source is attached to this row.

Source citations
Not stated
Background data
ecoinvent 3.12
Background dataset
tap water
Uncertainty
-33.3% / +66.7% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit
L
Nitrogen (N2) Process gaskg · -37.5% / +50%
Derivation basis
  • The model specifies this input from the production route, either from the chemistry of the reaction or from the allowance the route sets for it. It also states the excess the route uses and the share it recovers for reuse.

No source is attached to this row.

Source citations
Not stated
Background data
ecoinvent 3.12
Background dataset
nitrogen, liquid
Notes
Inert atmosphere for pyrophoric handling
Uncertainty
-37.5% / +50% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit
kg
Argon (Ar) Process gaskg · -60% / +100%
Derivation basis
  • The model specifies this input from the production route, either from the chemistry of the reaction or from the allowance the route sets for it. It also states the excess the route uses and the share it recovers for reuse.

No source is attached to this row.

Source citations
Not stated
Background data
ecoinvent 3.12
Background dataset
argon, liquid
Notes
Purging and blanketing
Uncertainty
-60% / +100% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit
kg

Outputs and waste

Wastewater to treatment WastewaterL · -58.3% / +177.7%
Derivation basis
  • The model estimates this flow from the mass balance of the operation and from the share of material the operation loses.

The sources below are this dataset's own bibliography. They are not tied to this row.

Source citations (dataset-level)
Inherited from this dataset's own bibliography, not tied to this row:
Background data
carried, no background dataset
Background dataset
wastewater, average
Uncertainty
-58.3% / +177.7% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit
L
Dimethylaluminum chloride residue Solid wasteg · -50% / +100%
Derivation basis
  • The model estimates this flow from the mass balance of the operation and from the share of material the operation loses.

The sources below are this dataset's own bibliography. They are not tied to this row.

Source citations (dataset-level)
Inherited from this dataset's own bibliography, not tied to this row:
Background data
ecoinvent 3.12 treatment route
Background dataset
treatment of hazardous waste, hazardous waste incineration, with energy recovery
Notes
The portion of the byproduct that is not recovered, hydrolysed before disposal. It is netted out of the co-product row rather than added on top of it.
Uncertainty
-50% / +100% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit
g
Gallium-containing residue Solid wasteg · -40% / +100%
Derivation basis
  • The model estimates this flow from the mass balance of the operation and from the share of material the operation loses.

The sources below are this dataset's own bibliography. They are not tied to this row.

Source citations (dataset-level)
Inherited from this dataset's own bibliography, not tied to this row:
Background data
ecoinvent 3.12 treatment route
Background dataset
Gallium recovery
Notes
Distillation bottoms carrying unrecovered gallium, sold to a reclaimer rather than disposed of. ecoinvent 3.12 publishes no gallium-scrap or gallium-reclamation market, so the row is linked to a generic metal-bearing sludge recovery service and that substitution is declared on the row: what the link represents is the handling of a metal-bearing residue by a recovery smelter, not any gallium content, and a reader must not take it as a supply of secondary gallium. Under the recyclable-byproduct cut-off convention the reclaim burden belongs to the next product system and no credit is taken here. The missing metal-specific dataset remains a declared gap.
Uncertainty
-40% / +100% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit
g
Spent solvent Solid wasteg · ±25%
Derivation basis
  • The model estimates this flow from the mass balance of the operation and from the share of material the operation loses.

The sources below are this dataset's own bibliography. They are not tied to this row.

Source citations (dataset-level)
Inherited from this dataset's own bibliography, not tied to this row:
Background data
ecoinvent 3.12 treatment route
Background dataset
treatment of hazardous waste, hazardous waste incineration, with energy recovery
Notes
Non-recoverable fraction of the working charge, equal to the make-up bought on the input side.
Uncertainty
±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit
g

Emissions to air

2 elementary flows released to air by this dataset's own operations. Quantities are not published; they ship with the dataset on Circa.

Trimethylgallium Emission to airg
Derivation basis
  • The model estimates this flow from the mass balance of the operation and from the share of material the operation loses.
  • No corresponding ecoinvent dataset or flow was identified for this entry, so it is published with its own quantity and no background link

No source is attached to this row.

Source citations
Not stated
Compartment
Air (non-urban air or from high stacks)
Formula
Ga(CH3)3
CAS number
1445-79-0
ecoinvent 3.12 elementary flow
Not stated
Notes
Pyrophoric; fugitives ignite and convert to Ga2O3
Uncertainty
A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit
g
Volatile organic compounds (VOC) Emission to airg
Derivation basis
  • The model estimates this flow from the mass balance of the operation and from the share of material the operation loses.

The sources below are this dataset's own bibliography. They are not tied to this row.

Source citations (dataset-level)
Inherited from this dataset's own bibliography, not tied to this row:
Compartment
Air (non-urban air or from high stacks)
ecoinvent 3.12 elementary flow
NMVOC, non-methane volatile organic compounds
Notes
Solvent fugitives from distillation
Uncertainty
A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit
g

Emissions to water

No emissions to water are recorded at this level.

Flows not quantified

No flows are recorded for this dataset without a quantity.

Limitations and unquantified flows (3)

Limits this dataset declares about itself: first any limit stated in its own description, then any limit it declares flow by flow, grouped by channel. Each entry below is the model's own disclosure.

  • The alkylating agent is charged with a deliberate excess, and about a seventh of the aluminium it brings in has no output flow as a result.
  • The optional potassium fluoride complexing agent brings potassium and fluorine into the process that no output flow carries.
  • The cooling-tower blowdown is now carried as a wastewater flow, but its dissolved load is not. The loop is non-contact and the synthesis is anhydrous, so nothing from the reaction reaches it; what the blowdown actually carries is the make-up water's own minerals concentrated up, plus the tower's biocide and scale inhibitor. Those depend on the site's intake water quality, which a global-average dataset cannot state, so the volume ships and the load does not.

The flows above are this dataset's own records. What follows are the scope rules set once for the whole database in the methodology report, repeated here so every dataset page carries them.

Boundary declared by this dataset

Gate-to-gate TMGa synthesis from GaCl3 + TMAl

Database-wide boundary policy — applies to every REEL dataset

These boundaries are set once for the whole database, in Chapter 2 of the methodology report, and apply to this dataset wherever they are relevant to it. The excluded flows listed above are specific to this dataset.

Use phase
Product operation is outside the cradle-to-gate scope.
End-of-life treatment
Recycling and disposal are outside the cradle-to-gate scope.
Distribution and retail
The gate is a finished component ready for integration into a higher-level assembly.
Inbound transport of raw materials
Transport of purchased raw materials to the manufacturing facility is already inside the upstream "market for" datasets that users link to a background database, so it is not modelled a second time here. This does not cover freight between REEL production stages, which is modelled where a dataset authors it.
Returnable shipping containers
Where freight between production stages is modelled, the mass moved is the product itself. The shipping container (FOSB, SEMI M31) is returnable capital equipment whose per-trip share is unsourced, so its tare is excluded from the transport effort.
Photomask fabrication
A mask set's embodied burden is amortised across a high-volume production run and is not attributed per wafer. Users assessing low-volume production should add mask fabrication separately; the methodology report gives the basis for the exclusion.
Employee transport, administration and R&D overhead
Employee transportation, facility administration and R&D/pilot-production overhead are outside scope.
Capital goods
Manufacturing equipment, cleanroom construction and facility infrastructure are excluded, on the grounds of absent public data on equipment embodied energy, uncertainty in equipment lifetime and allocation, common practice in electronics LCA, and a focus on the operational inventory. Future versions may include capital goods when sufficient public data becomes available.
Precious metal recovery credits
Scrap recovery credits for precious metals are excluded pending data availability.
Wafer reclaim
Test wafers and scrap are outside the system boundary.

Inside the boundary, linked rather than modelled

Silicon ingot growth and wafer slicing
Inside the cradle-to-gate scope, but treated as upstream material inputs linked to background databases rather than modelled as REEL processes.
Freight between production stages
Where a dataset's product moves between REEL production stages - wafer fabrication to the packaging site, for example - that leg is authored as a transport service and linked to an ecoinvent freight activity. It is measured as a transport effort in tonne-kilometres, not as a mass. Route distances are authored per route class with a stated band; a lower bound of zero is a modelling statement that the two sites can be co-located, not a missing value.

Cut-off criteria

A flow is excluded from a process inventory when it contributes less than 1 % of the total mass of inputs to that unit process, or less than 1 % of its total energy input. The denominator is total process inputs, not product mass. That distinction matters in semiconductor manufacturing, where the input mass of water, chemicals and gases greatly exceeds the product mass, so the threshold removes only genuinely minor flows.

Included regardless of the cut-off

  • Perfluorocarbons (CF4, C2F6, SF6, NF3) - high GWP, EPA regulated
  • Heavy metals (Pb, Cd, Hg, Cr(VI)) - RoHS regulated, high toxicity
  • Volatile organics (photoresist solvents, PGMEA) - air quality
  • Precious metals (Au, Ag, Pd, Pt) - high embodied impacts
  • Ozone-depleting substances (legacy CFCs, HCFCs) - Montreal Protocol