| HS Code | 872912 |
| Chemical Formula | Ga(CH3)3 |
| Molecular Weight | 114.83 g/mol |
| Cas Number | 1445-79-0 |
| Appearance | Colorless, clear liquid |
| Melting Point | -15.8 °C |
| Boiling Point | 55.8 °C |
| Density | 1.151 g/mL at 15 °C |
| Vapor Pressure | 184 mmHg (245 mbar) at 20 °C |
| Vapor Density | 3.96 (air = 1) |
| Solubility | Reacts with water; soluble in ethers, alkanes, and aromatic hydrocarbons |
| Reactivity | Pyrophoric; spontaneously ignites in air |
| Purity | ≥99.9999% (6N) electronic/EL grade |
| Metallic Impurities | Each metallic impurity typically < 0.1 ppm |
| Gallium Content | 60.72% by weight |
As an accredited Trimethylgallium (TMGa) Electronic/EL Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Trimethylgallium Electronic/EL Grade supplied in a 100g stainless steel bubbler cylinder under inert atmosphere, ready for MOCVD/ALD use. |
| Container Loading (20′ FCL) | 20′ FCL: TMGa secured in sealed stainless cylinders, inert-gas protected, upright, with hazmat labeling and compliant transport. |
| Shipping | Trimethylgallium (TMGa) Electronic/EL Grade ships as hazardous material in certified, sealed stainless steel cylinders or bubblers under inert gas. Because it is pyrophoric and water-reactive, air and moisture must be strictly excluded. Transport requires UN 3394 labeling, Class 4.2/4.3, Packing Group I, plus specialized hazmat documentation and authorized carriers. |
| Storage | Trimethylgallium (TMGa) is pyrophoric and moisture-sensitive. Store in sealed, corrosion-resistant cylinders under inert gas (nitrogen or argon) in a cool, dry, well-ventilated area away from ignition sources, water, and oxidizers. Use approved flammable-storage cabinets, ground containers, and handle only under inert atmosphere to prevent hazardous decomposition. |
| Shelf Life | Shelf life is typically 12 months when stored in original sealed cylinder, under inert gas, at recommended temperatures. |
Metalorganic chemical vapor deposition of GaN-on-sapphire LED epiwafers is the highest-volume downstream consuming point for electronic-grade trimethylgallium. In the conventional two-step growth sequence on 4 in or 6 in c-plane patterned sapphire substrates, a low-temperature GaN nucleation layer is first deposited at 500–600 °C from TMGa and ammonia, then annealed as the reactor ramps to 1000–1100 °C. High-temperature GaN buffer layers, n-GaN contact layers, and p-GaN cladding layers are subsequently grown at chamber pressures between 100 Torr and 400 Torr, with V/III ratios from 1000:1 to 5000:1. Growth rates for high-quality GaN on production-scale multi-wafer platforms are typically 1–4 µm/h, with the TMGa molar flow adjusted against reactor geometry and wafer carrier capacity. EL-grade TMGa with total trace metal contamination below 0.1 ppm is required because zinc, silicon, magnesium, and iron form shallow or deep recombination centres in the finished LED epilayer.
| Parameter | Electronic/EL Grade Control Range | Analytical Method |
|---|---|---|
| Assay | ≥99.9999% (6N) | ICP-MS / ICP-OES |
| Trace metals per element | <0.01 ppm | ICP-MS |
| Oxygen | <0.1 ppm | FTIR |
| Moisture | <0.1 ppm | FTIR / cavity ring-down |
| Particles | ≤5 particles/cm³ ≥0.1 µm | Laser particle counter, ISO 14644-1 Class 5 |
TMGa is delivered from a stainless-steel bubbler equipped with a dip tube and pressure-controlled outlet. Hydrogen carrier gas is metered through the bubbler at a temperature maintained between 10 °C and 20 °C, with head pressure typically between 0.5 barg and 1.5 barg to stabilise vapour concentration during long batch runs. Heated downstream gas lines prevent condensation before the reactor inlet. InGaN quantum-well layers in blue and green LED structures normally use triethylgallium because indium incorporation requires growth temperatures below 850 °C, whereas the GaN barriers and cladding layers around the quantum wells are TMGa-grown. Terminal packaged LED configurations include SMD 2835, 3030, 5050, and chip-on-board arrays; these devices are qualified under IES LM-80 lumen-maintenance protocols and supplied for general illumination, automotive forward lighting, and high-density display backlighting.
Depletion-mode AlGaAs/GaAs pseudomorphic high-electron-mobility transistor epiwafers require low carbon background concentration and high electron mobility in the two-dimensional electron gas. MOCVD of pHEMT structures uses TMGa for GaAs buffer and contact layers, trimethylaluminium for AlGaAs barrier and spacer layers, and arsine as the group-V source. Typical growth temperatures range from 600 °C to 750 °C, chamber pressure from 20 Torr to 100 Torr, and V/III ratios from 20:1 to 80:1. TMGa-derived methyl radicals are the dominant carbon source in GaAs growth; carbon incorporates as a shallow acceptor and compensates silicon donors in the channel region. To suppress carbon incorporation below 1×1015 cm-3, arsine partial pressure and V/III ratio are increased while growth rate is reduced. Oxygen contamination from TMGa or carrier gas disrupts AlGaAs barrier integrity because deep-level oxygen complexes reduce 300 K electron mobility and raise sheet resistance. Published Hall data for AlGaAs/GaAs two-dimensional electron gas structures fall below 6000 cm²/V·s; pseudomorphic InGaAs channel variants reach 6000–8500 cm²/V·s at sheet carrier density of 1×1012–2×1012 cm-2. These values are only reproducible when TMGa oxygen and moisture are maintained under <0.1 ppm. Terminal RF front-end modules for n77, n79, and millimeter-wave bands integrate low-noise amplifiers and switches fabricated from these epiwafers; qualification follows JEDEC JESD22-A104 temperature cycling and AEC-Q101 for automotive-grade variants.
In gallium arsenide-based vertical cavity surface emitting laser production, TMGa is metered into a multi-wafer MOCVD reactor to grow the AlGaAs/GaAs distributed Bragg reflector stacks and n-type GaAs contact layers. Growth temperature for VCSEL DBR mirrors is generally 700–800 °C, pressure 50–100 Torr, and V/III ratio 50:1–150:1; quarter-wave AlGaAs and GaAs layer pairs are deposited sequentially to build the top and bottom mirrors. Bottom-emitting 940 nm VCSEL structures for three-dimensional sensing use 20–40 AlGaAs/GaAs mirror pairs per DBR and an active region containing InGaAs quantum wells. TMGa purity directly affects cavity loss because trace iron or cobalt in the DBR layers forms mid-gap centres that increase absorption at the emission wavelength. Device evaluation for laser safety and performance is performed under IEC 60825-1; production fall-out is monitored by wafer-level photoluminescence mapping at the lasing wavelength. Terminal products include flood illuminators, dot projectors, LiDAR sources, and 850 nm datacom transceivers.
Gallium nitride power high-electron-mobility transistors on 6 in or 8 in silicon (111) substrates use TMGa as the gallium source for high-temperature GaN buffer and channel layers. Triethylgallium is sometimes employed for low-temperature pulsed growth, but TMGa is retained for the bulk GaN buffer because its pyrolysis efficiency above 1000 °C is higher and its methyl-derived carbon content can be tuned for resistive buffer doping. The Si(111) surface requires an aluminium nitride nucleation layer grown with trimethylaluminium at 900–1000 °C to prevent gallium meltback attack. A graded AlGaN transition stack is then inserted before the GaN buffer to balance tensile stress from the coefficient of thermal expansion mismatch between silicon at 2.6×10-6 K-1 and GaN at 5.6×10-6 K-1.
TMGa-based GaN buffer growth proceeds at 1000–1100 °C and 100–400 Torr, with V/III ratios of 1000:1–3000:1; growth rate is limited to 1–3 µm/h to preserve wafer bow below ±50 µm across an 8 in wafer. Carbon released from TMGa pyrolysis may be intentionally incorporated as a compensating acceptor in the GaN buffer to achieve resistivity above 1×106 Ω·cm, reducing buffer leakage and improving off-state blocking. Oxygen and moisture in TMGa must remain below <0.1 ppm because they form donor-like defects that compensate carbon and degrade vertical isolation. In situ reflectometry and wafer-bow measurement on the reaction chamber provide real-time feedback for stress control. Resulting 650 V pGaN-gate normally-off HEMTs are qualified under JEDEC JC-70 and AEC-Q101 for USB-C adapters, data center power supplies, and on-board chargers.
| Application | Substrate Temperature | Chamber Pressure | V/III Ratio | Primary Impurity Sensitivity |
|---|---|---|---|---|
| GaN-on-sapphire LED | 1000–1100 °C | 100–400 Torr | 1000:1–5000:1 | Oxygen, Mg, Zn, Si recombination centres |
| AlGaAs/GaAs pHEMT | 600–750 °C | 20–100 Torr | 20:1–80:1 | Carbon compensation, oxygen deep levels |
| GaN-on-Si power HEMT | 1000–1100 °C | 100–400 Torr | 1000:1–3000:1 | Oxygen donor defects, carbon buffer control |
| InGaP/GaAs HBT | 550–700 °C | 50–100 Torr | 30:1 | Silicon and zinc in carbon-doped base |
| VCSEL DBR | 700–800 °C | 50–100 Torr | 50:1–150:1 | Iron, cobalt mid-gap absorption |
Bipolar transistor structures for 5G sub-6 GHz handset and Wi-Fi 6/6E front-end modules rely on InGaP/GaAs heterojunction bipolar transistor epiwafers. MOCVD growth uses TMGa for the GaAs collector and base layers, trimethylindium plus TMGa for the InGaP emitter, and phosphine or tertiarybutylphosphine as the group-V source. Growth temperatures are kept at 550–700 °C to minimise zinc diffusion from the p-GaAs base into the emitter, with chamber pressure of 50–100 Torr and V/III ratio near 30:1 for high-quality GaAs. Carbon doping in the base is required at 1×1019–4×1019 cm-3 to reduce base sheet resistance; TMGa methyl radicals provide intrinsic carbon, but precise control is obtained with external carbon tetrabromide or carbon tetrachloride doping lines. TMGa purity influences base contact resistance and emitter-base leakage. Trace silicon from TMGa can compensate the carbon-doped p-GaAs base and increase base resistance; trace zinc can diffuse into the InGaP emitter and produce secondary turn-on. Therefore EL-grade TMGa with Si <0.01 ppm and Zn <0.01 ppm is specified on the certificate of analysis. Terminal HBT wafers are used in power amplifier modules that combine HBT and pHEMT on a single GaAs die, tested according to 3GPP conformance procedures for handset transmit power and linearity.
Red-orange high-brightness AlGaInP LED epiwafers are produced by phosphine-based MOCVD on GaAs substrates using TMGa as the gallium source. Growth of AlGaInP quantum well and confinement layers takes place between 700 °C and 800 °C, at 50–100 Torr, with phosphine partial pressure high enough to suppress indium desorption and maintain V/III ratios above 100:1. TMGa purity is critical because oxygen and moisture in the source line form non-radiative aluminium-oxygen complexes in the AlGaInP active region and reduce internal quantum efficiency at 615–630 nm. The epi process uses n-type GaAs substrates, a lattice-matched AlGaInP active region, and GaP window layers; final chips are employed in automotive tail lamps, signage, horticultural lighting, and small-format displays, where device qualification often follows AEC-Q102 for automotive optoelectronic components.
Beta-phase gallium oxide MOCVD using TMGa has been investigated for high-voltage Schottky barrier diodes and deep-ultraviolet photodetectors. In this route, TMGa vapor and an oxygen source are co-injected into a reactor at substrate temperatures from 700 °C to 900 °C. The oxygen-to-gallium ratio is a central control variable: ratios above 100:1 are typically required to suppress gallium suboxide formation and to stabilise the β phase on sapphire or native β-Ga₂O₃ substrates. However, published data for this specific configuration is limited; most reported TMGa-based Ga₂O₃ MOCVD is at pilot scale rather than high-volume production. TMGa purity below 6N with moisture under <0.1 ppm is necessary to avoid silicon and oxygen-related donor fluctuations that shift the electrode-metal Schottky barrier height. Terminal devices include experimental 1 kV-class Schottky barrier diodes and solar-blind photodetectors with cutoff below 280 nm; reliability testing remains aligned with AEC-Q101 for early automotive power qualification.
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Trimethylgallium (TMGa) Electronic/EL Grade is a pyrophoric organometallic source compound with CAS registry 1445-79-0 and molecular formula Ga(CH₃)₃. The compound is supplied as a clear, colourless liquid under high-purity inert gas, with a molecular mass of 114.83 g/mol, freezing point of -15.8 °C, boiling point of 55.7 °C at 101.3 kPa, density of approximately 1.15 g/cm³ at 20 °C, and vapour pressure of approximately 20.5 kPa at 20 °C. The Electronic/EL grade designation identifies a precursor intended for metalorganic chemical vapor deposition (MOCVD) and metalorganic vapor phase epitaxy (MOVPE) of III-V compound semiconductor layers, particularly GaAs, AlGaAs, InGaP, and GaAsP heterostructures. The product is not a single universal part number; supplier catalogue codes typically encode the purity grade, fill size, and bubbler configuration. Representative packaging includes electropolished 316L stainless-steel bubblers with fill masses from 100 g to 2.5 kg, fitted with metal-sealed, high-purity valves. Qualification of a specific supplier lot must be based on the certificate of analysis, not the catalogue designation alone.
The differentiation is primarily analytical. Electronic/EL grade material is controlled for trace metals, volatile organic impurities, particulates, and water-reactive residues to levels compatible with optoelectronic device performance. Vendor certificates of analysis typically report purity on a metals basis of 6N (99.9999%) or higher, with individual silicon, zinc, and sulfur concentrations below 1 ppmw and frequently below 0.5 ppmw. The residual alkali and transition-metal burden is measured by inductively coupled plasma mass spectrometry after controlled hydrolysis in an inert glovebox. Because no single ASTM or ISO method governs TMGa purity, the analytical method must be reviewed against NIST-traceable calibrants and the supplier’s limit of quantitation. Technical-grade material may contain total metal impurities at 10–100 ppmw or higher, which is acceptable for non-electronic synthesis but can introduce deep-level donors or acceptors in epitaxial films.
The Electronic/EL grade also differs in gas-handling compatibility and particle control. Electropolished wetted surfaces, metal-sealed valve stems, and baked container assemblies reduce moisture retention and particulate shedding. Leak-tightness of the bubbler and valve assembly is often specified at less than 1 × 10-9 mbar·L/s helium leak rate. Table 1 lists a representative specification envelope for Electronic/EL grade TMGa. Acceptance limits are supplier-specific and are not universal; the table should be read as typical published criteria for high-purity optoelectronic and electronic applications.
| Parameter | Typical acceptance envelope | Analytical method |
|---|---|---|
| Purity, metals basis | 6N (99.9999%) minimum | ICP-MS |
| Total trace metal impurities | ≤ 1.0 ppmw | ICP-MS |
| Silicon | ≤ 0.5 ppmw | ICP-MS |
| Zinc | ≤ 0.2 ppmw | ICP-MS |
| Sulfur | ≤ 0.2 ppmw | ICP-MS |
| Volatile organic impurities | ≤ 10 ppmw | GC-MS/FTIR |
| Particles ≥ 0.5 µm | ≤ 10 particles/mL | Optical particle counter |
Under typical fab gas-cabinet conditions, TMGa Electronic/EL Grade is maintained at bubbler temperatures between 0 °C and 20 °C. Hydrogen or nitrogen carrier gas is passed through the bubbler at mass-flow-controlled rates; the resulting gas stream is diluted and delivered to the reactor injection manifold. Carrier gas moisture must remain below 10 ppb and oxygen below 10 ppb at the point of connection to prevent hydrolysis of the alkyl and formation of gallium hydroxide or oxide particles. Because the material is pyrophoric and reacts violently with water, alcohols, amines, and halocarbons, all transfer operations require an inert atmosphere, double-valved disconnect fittings, and purged gas panels. Exhaust from the delivery panel and reactor must be directed to a thermal abatement unit or a wet scrubber rated for pyrophoric metalorganic service.
In GaAs and AlGaAs MOCVD, TMGa is combined with arsine in a hydrogen carrier gas at substrate temperatures between 600 °C and 800 °C. Typical reactor pressures range from 50 mbar to 200 mbar, with V/III ratios from 20 to 100; deposition rates of 1–4 µm/h are common in production-scale planetary and high-speed rotating-disc reactors. For InGaP and GaAsP, phosphine is substituted for or mixed with arsine, and growth temperatures are often reduced to 600–700 °C to limit indium desorption when trimethylindium is used as the Group III co-precursor. In Al-rich AlGaAs layers, oxygen and moisture ingress above 0.1 ppm in the reactor ambient is known to increase aluminum-oxygen incorporation, which degrades photoluminescence efficiency. The use of Electronic/EL grade precursor alone is therefore insufficient without leak-tight reactor and carrier-gas purification.
Production-scale experience on commercial multiwafer systems such as Aixtron Crius, Veeco Turbodisc, and Taiyo Nippon Sanso horizontal reactors shows that batch-to-batch variation in silicon and sulfur content can shift background carrier concentration in unintentionally doped GaAs. A precursor lot with silicon at 0.5 ppmw may still produce measurable n-type background if downstream gas handling does not remove silane or chlorosilane residues. For heterojunction bipolar transistor and high-electron-mobility transistor structures, qualification campaigns typically compare the precursor lot against Hall mobility and secondary-ion mass spectrometry profiles using a standard structure grown on 6-inch or 8-inch GaAs substrates. Published data for a specific reactor configuration is limited; accordingly, fabs maintain internal lot-to-lot acceptance criteria.
A direct substitution of triethylgallium (TEGa) for TMGa is not neutral. TEGa exhibits a lower vapour pressure than TMGa, which reduces bubbler delivery capacity at a given temperature and demands higher bubbler temperature or higher carrier-gas flow to achieve the same molar supply. Table 2 lists representative physical delivery properties for the two gallium alkyls.
| Property | TMGa | TEGa |
|---|---|---|
| CAS registry | 1445-79-0 | 1115-99-7 |
| Molecular mass | 114.83 g/mol | 156.91 g/mol |
| Boiling point at 101.3 kPa | 55.7 °C | 143 °C |
| Freezing point | -15.8 °C | -82.5 °C |
| Vapour pressure at 20 °C | 20.5 kPa (approx.) | 0.7 kPa (approx.) |
The higher TMGa vapour pressure is advantageous in multiwafer reactors where stable Group III partial pressure must be maintained at high carrier-gas flows. However, TEGa is often preferred for GaN-based devices because the ethyl radical dissociation pathway reduces carbon incorporation relative to methyl radical chemistry under comparable growth conditions. In GaAs and AlGaAs grown with TMGa, carbon can also act as an intentional p-type dopant when carbon tetrachloride or carbon tetrabromide is introduced; the background carbon level from TMGa is process-temperature- and V/III-dependent. Published comparative data from low-pressure MOCVD indicate that TEGa can lower unintentional carbon in GaAs at lower growth temperatures, but the exact magnitude depends on reactor geometry, arsine partial pressure, and pre-cracking conditions.
Delivery performance is governed by bubbler pressure drop, temperature control, and carrier-gas purity. A stabilized bubbler bath at ±0.1 °C is typical for electronic-grade precursor delivery because vapour pressure is strongly temperature-dependent; a temperature deviation of 1 °C can shift TMGa vapour concentration by more than 5%. Mass flow controllers must be calibrated for the actual carrier gas and must not contain elastomeric seals in wetted flow paths. The bubbler dip-tube and outlet valve should be purged with 60–100 cycles of high-purity inert gas after installation to remove adsorbed moisture and residual atmosphere. When ambient relative humidity exceeds 60%, connection operations require additional purge time and may require a dry-gas glovebag to prevent moisture condensation on fittings.
Thermal exposure limits are set not only by decomposition but also by the risk of container overpressure. Although TMGa does not undergo rapid decomposition at room temperature, intentional heating above 50 °C can promote exchange reactions and residue formation in the presence of trace oxygen or moisture. Storage is therefore specified at 15–25 °C in a ventilated, fire-rated cabinet. Incompatibilities include water, alcohols, amines, halocarbons, and oxidizing gases. Contact with water releases methane and gallium oxide/hydroxide solids; contact with air can ignite the liquid. Spill control must use dry sand, vermiculite, or a metalorganic-specific inert absorbent, never water or aqueous neutralizers.
The certificate of analysis for a 6N TMGa lot is necessary but not sufficient. A precursor lot can meet all ICP-MS limits and still produce unacceptable drift in MESFET or high-electron-mobility transistor threshold voltage if trace volatile impurities or particle bursts occur during delivery. Production fabs therefore combine supplier analytical data with reactor qualification on standard GaAs calibration structures. Hall-effect measurements at 300 K and 77 K, electrochemical capacitance-voltage profiling, and secondary-ion mass spectrometry are used to establish background doping and mobility. SIMS detection limits for silicon, zinc, and sulfur are typically in the 1015–1016 atoms/cm³ range, which is sufficiently sensitive for qualifying electronic-grade lots. Published data for a specific reactor type and precursor lot is limited; internal lot qualification remains the controlling practice.
Operational boundaries for Electronic/EL Grade TMGa are therefore defined by the complete delivery chain: bubbler cylinder, purge panel, mass flow controller, reactor inlet, and abatement. The material must not be exposed to ambient air, moisture above 10 ppb in the carrier gas, or incompatible gases. Personnel training must include pyrophoric-liquid emergency response and the facility must maintain a documented safe-use review under the applicable fire code and SEMI S2 equipment safety guidance. No claim of fitness for a particular epitaxial process is made solely from the product designation; qualification must be demonstrated on the intended reactor and device stack.
