| HS Code | 782133 |
| Chemical Formula | N₂O |
| Molecular Weight | 44.013 g/mol |
| Cas Number | 10024-97-2 |
| Grade | Electronic/EL Grade |
| Purity | ≥99.999% |
| Appearance | Colorless gas |
| Odor | Slightly sweet |
| Melting Point | -90.86 °C |
| Boiling Point | -88.48 °C |
| Solubility In Water | 1.5 g/L at 20 °C |
As an accredited Nitrous Oxide (N₂O) Electronic/EL Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Nitrous Oxide (N₂O) Electronic/EL Grade is supplied in disposable 2.2 L steel cylinders containing 1.1 kg high-purity gas. |
| Container Loading (20′ FCL) | Loading a 20ft FCL with electronic-grade Nitrous Oxide cylinders: upright, secured, ventilated, with proper hazmat placards and documentation. |
| Shipping | Nitrous Oxide (N₂O) Electronic/EL Grade ships as a liquefied compressed gas in high-pressure DOT-approved cylinders. Transport requires hazmat classification, leak-proof connections, proper labeling, and secure upright placement. Stock lead times may apply due to specialized gas handling and regulated logistics. Verify destination compliance before dispatch. |
| Storage | Nitrous Oxide (N₂O) Electronic/EL Grade must be stored upright in secured, well-ventilated areas, away from heat, sparks, and open flames. Keep cylinders below 52°C, protected from physical damage, and segregated from incompatible materials. Use proper valve caps and ensure leak-free connections. Store in a cool, dry location with appropriate gas detection and fire safety equipment. |
| Shelf Life | Shelf life: 24 months from manufacture if stored properly in sealed cylinder, away from heat and contaminants. |
Electronic-grade N₂O is consumed in semiconductor and MEMS fabrication as a high-purity oxygen source for plasma and thermal oxide formation. In intermetal dielectric PECVD, SiH₄ and N₂O are delivered through mass flow controllers to a parallel-plate showerhead reactor operated at 13.56 MHz. Complete oxidation of one mole of silane to SiO₂ consumes 2.0 mol of N₂O or 1.0 mol of O₂, so the production-favored N₂O/SiH₄ ratio of 12:1 to 25:1 is not dictated solely by oxygen balance. The excess N₂O dilutes silane in the gas phase, reduces premature powder nucleation, and maintains a stoichiometric film. On 200 mm and 300 mm tools, substrate temperature is held between 250 °C and 400 °C, chamber pressure is 2.0–4.0 Torr, and RF power density is 0.3–1.2 W/cm². If wafer temperature drifts by more than ±5 °C, the refractive index can shift because film density and Si-OH content respond to surface temperature. Typical film properties include refractive index 1.46–1.47, compressive stress, and wet etch rate in 6:1 buffered HF of 2–4 times thermal oxide. FTIR inspection per ASTM E1252-98(2013) shows Si-O-Si asymmetric stretching near 1070 cm⁻¹; the Si-OH stretching band near 3650 cm⁻¹ is held below detection. The terminal structure is the intermetal dielectric, passivation layer, or sidewall spacer in logic, analog, and memory devices. EL-grade N₂O compliance for this application is set by wafer-fab gas purchasing specifications, commonly requiring lot-certified moisture below 0.5 ppmv, CO₂ below 0.5 ppmv, total hydrocarbons below 1 ppmv, and point-of-use particle filtration compatible with ISO 14644-1:2015 Class 3 delivery lines.
In shallow trench isolation fill for technologies where HDP-CVD is selected, SiH₄, O₂, Ar, and EL-grade N₂O are ionized in a high-density inductively coupled plasma source. The wafer platen is biased to create directional Ar⁺ sputtering that removes overhang material from trench corners during deposition. Pressure is maintained at 1–10 mTorr, substrate temperature at 300–450 °C, and platen power at 1000–3000 W on 200 mm tools. N₂O typically constitutes 10–30% of the total oxygen source flow, with the balance supplied as O₂. The function of N₂O is not to increase deposition rate but to modify the oxygen radical distribution and suppress silicon-rich oxide formation without excessively reducing deposition rate. A high N₂O fraction can leave residual nitrogen in the oxide; XPS analysis of the N 1s region near 398 eV is used to reject bulk nitrogen incorporation because nitrogen-rich oxide exhibits higher wet etch rate and unstable dielectric behavior. The sputter-to-deposition ratio is adjusted through platen bias and oxygen-source flow; excessive sputtering damages the active silicon, while insufficient sputtering produces pinch-off voids. The terminal product is a void-free filled trench oxide, typically for trench widths from 100 nm to 500 nm, followed by chemical mechanical planarization to a nitride stop layer. The EL-grade N₂O source is restricted to metal impurity levels below 10 ppbv per element because ion bombardment can sputter gas-borne metal contamination into the trench sidewall. No single N₂O flow setting is universal; process qualification on the specific HDP platform determines the upper N₂O limit before nitrogen-related etch rate increase exceeds the oxide removal tolerance.
| Application segment | Substrate temperature range | Chamber pressure range | N₂O-based feed ratio | Terminal control target |
|---|---|---|---|---|
| PECVD intermetal dielectric | 250–400 °C | 2.0–4.0 Torr | N₂O/SiH₄ 12:1–25:1 | refractive index 1.46–1.47 |
| HDP-CVD shallow trench isolation | 300–450 °C | 1–10 mTorr | N₂O 10–30% of oxygen source | void-free fill, 100–500 nm trench width |
| Furnace oxynitridation | 800–1100 °C | 760 Torr or reduced pressure | N₂O tube flow 0.5–10 slm | equivalent oxide thickness 2.0–7.0 nm |
| MEMS sacrificial oxide | 150–250 °C | 0.5–2 Torr | N₂O/SiH₄ 20:1–30:1 | vapor HF selectivity 100:1 or higher |
| Silicon oxynitride waveguide | 250–350 °C | 0.5–3 Torr | N₂O flow adjusted against NH₃/SiH₄ | refractive index 1.45–1.70 at 632.8 nm |
The use of N₂O in vertical thermal furnace oxidation creates a nitrided silicon dioxide layer at the Si/SiO₂ interface. Wafers are processed in a vertical diffusion furnace at 800–1100 °C, with N₂O flow between 0.5 slm and 10 slm depending on tube size and load configuration. N₂O pyrolysis generates NO, which reacts with silicon to form a nitrogen-containing interfacial zone. The nitrogen dose is typically 1–4 at.% localized within 1–2 nm of the silicon interface. This interfacial nitrogen acts as a diffusion barrier against boron penetration from p-type polysilicon gates and improves hot-carrier resistance. Growth rate in N₂O is lower than in O₂ because nitrogen at the interface blocks oxidant transport, so oxidation time must be extended by approximately 20–40% to reach the target equivalent oxide thickness. The process is monitored by single-wavelength ellipsometry and X-ray photoelectron spectroscopy for nitrogen areal density. High wafer-load temperature nonuniformity or gas-flow recirculation can produce oxide thickness variation across the load. The terminal product is a gate dielectric for CMOS, power management, and analog devices with equivalent oxide thickness from 2.0 nm to 7.0 nm. EL-grade N₂O for furnace oxynitridation is controlled for moisture below 0.5 ppmv, CO₂ below 0.5 ppmv, and total hydrocarbons below 1 ppmv; particles are removed through point-of-use filters with 0.003 μm retention. Trace carbon dioxide or moisture changes the NO partial pressure, alters nucleation uniformity, and increases defect density on large-diameter wafers.
Low-temperature PECVD SiO₂ from SiH₄ and N₂O is used as a sacrificial release layer in MEMS fabrication because vapor HF removes it selectively against silicon and silicon nitride. Deposition is performed at 150–250 °C, chamber pressure 0.5–2 Torr, and RF power density 0.1–0.5 W/cm². The N₂O/SiH₄ ratio is maintained between 20:1 and 30:1 to suppress hydrogen incorporation and avoid cracking after release. Film stress is adjusted by splitting low-frequency and high-frequency RF power; increasing low-frequency power produces higher ion bombardment, densification, and a shift toward compressive stress. The sacrificial oxide thickness defines the air gap or standoff height in accelerometers, micromirrors, pressure sensors, and RF MEMS devices. After structural layer deposition and patterning, the sacrificial oxide is removed in vapor HF at 35–45 °C to release the silicon element. Etch selectivity over silicon is typically 100:1 or higher. The terminal product is a freestanding silicon structure with no oxide residue. EL-grade N₂O used for this process is qualified for maximum transition metal content of 10 ppb per element because metal contamination changes vapor HF etch rate and leaves nonvolatile post-release residues. Moisture ingress in the N₂O delivery line raises Si-OH content, increases film porosity, and produces stringer defects after release. Scanning electron microscopy and white-light interferometry are used to inspect released devices for stiction, bow, and residue.
Silicon oxynitride waveguides are deposited from SiH₄, N₂O, and NH₃; the N₂O flow fraction determines the oxygen-to-nitrogen ratio and therefore the core refractive index. On 200 mm wafers, deposition temperature is constrained to 250–350 °C for back-end compatibility, pressure is 0.5–3 Torr, and index is tuned between 1.45 and 1.70 at 632.8 nm. Increasing N₂O relative to NH₃ lowers nitrogen content and reduces N—H absorption, but also reduces the refractive index and increases compressive stress. The process window is bounded on one side by N—H overtone absorption in the 1480–1520 nm telecom band and on the other side by polarization-dependent loss from stress birefringence. Film characterization includes ellipsometric thickness, FTIR measurement of N—H stretching intensity, and optical loss measurement at 1310 nm and 1550 nm. The terminal product is a waveguide core clad with silica, used in optical transceivers, splitters, and photonic integrated circuits. EL-grade N₂O for this application is specified with CO₂ below 0.1 ppmv because carbonaceous defects raise optical absorption. The N₂O source gas is also filtered to 0.003 μm; particle-induced core defects cause scattering loss. Published data for specific low-N—H formulations on production photonic platforms is limited, so optical loss targets are qualified wafer-by-wafer rather than inferred from gas purity alone.
For transition-metal-oxide resistive random access memory stacks, N₂O-containing remote plasma processes partially oxidize Hf, Ta, or TiN electrode surfaces before deposition of the switching layer. The remote plasma source operates at 2.45 GHz microwave or 13.56 MHz RF, with N₂O flow between 50 sccm and 500 sccm. Substrate temperature is held below 150 °C to prevent overoxidation of the base metal. The process forms a 1–3 nm metal-oxide interfacial layer that stabilizes the resistance window and reduces forming voltage. Oxygen dose is controlled by process time in the range 10–60 s and monitored through optical emission spectroscopy of the O 777 nm line intensity. Overoxidation produces an insulating interfacial layer that increases initial resistance and programming current. EL-grade N₂O with moisture below 0.1 ppmv and transition metals below 10 ppbv is required because hydroxyl groups and metal impurities degrade endurance and data retention. The terminal product is a nonvolatile memory cell integrat, but the oxidation step alone does not define memory behavior; subsequent capping electrode quality and post-metallization annealing are equally critical. The same remote plasma oxidation concept has been adapted to copper diffusion barrier treatment, although published data for those configurations is limited and qualification is performed on a line-by-line basis.
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Nitrous Oxide (N2O) Electronic/EL grade is a high-purity oxidizing gas supplied to semiconductor front-end, compound semiconductor, and advanced packaging process lines where trace oxygen, moisture, hydrocarbon, and metal contamination directly affect deposited-film electrical performance and defect density. Product codes are supplier-specific but usually encode cylinder size and valve type; an example designation, EL-N2O-44L-CGA326, denotes a 44 L cylinder with a CGA 326 outlet. Electronic/EL grade material is separated from medical and industrial grades by tighter limits on moisture, total hydrocarbons, nitrogen oxides, and metal impurities, with typical certified purity at ≥99.999% or 99.9995% and total hydrocarbons specified below 0.5 ppmv. The product is used in plasma-enhanced chemical vapor deposition, low-pressure chemical vapor deposition, atomic layer deposition, furnace oxidation, and etch/diffusion processes that demand low particle contribution and stable mass flow delivery. Compliance claims are generally evaluated under the SEMI C3 gas specification framework, supported by batch certificates issued from analytical operations accredited to ISO/IEC 17025.
Electronic/EL grade specifications are not universally fixed; each manufacturer maintains a certificate-of-analysis template with agreed limits. The table below lists commonly observed specification limits for high-purity nitrous oxide used in wafer fabrication. Moisture detection is typically performed by cavity ring-down spectroscopy or atmospheric pressure ionization mass spectrometry. Oxygen, nitrogen, carbon monoxide, carbon dioxide, and total hydrocarbons are measured by gas chromatography with a pulsed discharge helium ionization detector. Nitrogen oxides are measured by Fourier transform infrared spectroscopy, and trace metals by inductively coupled plasma mass spectrometry after collection. Values are maximum allowable concentrations unless otherwise noted. Limits can vary by instrumentation and fab qualification; analytical uncertainty should be verified against the vendor's ISO/IEC 17025 scope.
| Parameter | Typical electronic/EL limit | Analytical technique |
|---|---|---|
| Purity | ≥99.999% minimum; 99.9995% optional | Difference calculation |
| Water (H2O) | <1 ppmv | CRDS / APIMS |
| Oxygen (O2) | <0.5 ppmv | GC-PDHID |
| Nitrogen (N2) | <1 ppmv | GC-PDHID |
| Carbon monoxide (CO) | <0.5 ppmv | GC-PDHID / FTIR |
| Carbon dioxide (CO2) | <0.5 ppmv | GC-PDHID / FTIR |
| Total hydrocarbons as CH4 | <0.5 ppmv | FID |
| NO/NOx | <0.5 ppmv | FTIR |
| Ammonia (NH3) | <0.5 ppmv | FTIR / ion chromatography |
| Total metals (Fe, Ni, Cr, Cu, Na, K, Ca) | <10 ppbw | ICP-MS |
| Particles ≥ 0.1 µm | <3 particles/ft³ | Optical particle counter |
Purity calculated by difference from measured impurities can understate high-molecular-weight or nonvolatile contamination if those species are not included in the standard panel. Published data for specific fab yield improvements at moisture levels below 0.1 ppmv is limited; therefore, acceptance limits are frequently established through line qualification with mass spectrometric or CRDS sampling at the point of use rather than from cylinder certificates alone. Gas-phase moisture can be generated by surface desorption from cylinder walls, valve components, and distribution lines, so heat cycling and purge protocols are necessary to maintain the stated limit after cylinder hookup. Analytical detection limits are below the specification limits by at least one order of magnitude in qualified semiconductor gas laboratories. Moisture analyzers based on CRDS have typical lower detection below 100 ppt, and APIMS can reach below 10 ppt for moisture and oxygen in research-grade distribution lines. GC-PDHID methods for permanent gases typically report detection limits below 10 ppb.
Delivery of electronic-grade N2O to the point of use requires a gas distribution system that preserves internal cleanliness and avoids pressure instability. Electropolished 316L stainless steel containers with an internal surface finish below 0.25 µm Ra and low-outgassing valve seats are typical for electronic/EL service. Cylinder water capacity in electronic/EL service commonly ranges from 10 L to 49 L; high-volume fabs receive bulk supplies in ISO containers or tube trailers with similar analytical controls. The cylinder valve outlet is matched to the gas service; in North America a CGA 326 connection is common, while regional gases use alternate national connections. Pressure regulation is performed with metal-diaphragm regulators rather than elastomer-seated designs. Mass flow controllers should be calibrated with N2O or corrected using the instrument vendor's gas-specific correction factor; operating on nitrogen calibration without correction produces delivery errors.
Because N2O has a critical temperature of 36.4 °C and critical pressure of 72.4 bar, cylinder pressure is vapor-pressure dependent. At 20 °C, saturated vapor pressure is approximately 50.6 bar. Sustained high-flow vapor withdrawal removes latent heat, lowers cylinder temperature, and can reduce downstream pressure during long process runs. Gas cabinets therefore provide temperature-controlled enclosures, cylinder warmers for high vapor-withdrawal rates, and pressure-based automatic switchover to maintain stable inlet pressure to the process tool. Production-scale gas cabinets can exhibit transient pressure decay during high-flow N2O draws if cylinder warmers are undersized; this failure mode appears as unstable mass flow controller output and film thickness variation at the wafer edge. Cylinder change-out procedures include purge with high-purity inert gas, leak testing with helium, and verification of moisture and oxygen levels before release to the process line. A leak rate of 1 × 10-9 Pa·m³/s or better is a common acceptance criterion for semiconductor gas line components.
The distinction between electronic/EL grade and lower-purity grades is not solely total assay. Medical and industrial nitrous oxide may show acceptable bulk assay for their intended use but fail semiconductor specifications for moisture, hydrocarbon residues, and metals. Electronic/EL is managed as a high-purity process gas under SEMI C3 expectations; medical grade is controlled by pharmacopeial standards such as USP-NF; industrial grade is generally supplied under national compressed gas purity standards without wafer-level moisture, hydrocarbon, or metal limits. The table below summarizes the principal control differences.
| Attribute | Electronic/EL | Medical USP-NF | Industrial |
|---|---|---|---|
| Minimum purity | ≥99.999% | ≥99.0% | ≥99.0% |
| Moisture | <1 ppmv | Not specified as ppmv | Not specified |
| Hydrocarbons | <0.5 ppmv as CH4 | Not specified | Not specified |
| Metal impurities | <10 ppbw total | Not specified | Not specified |
| Particle control | Specified for ≥ 0.1 µm particles | Not normally specified | Not normally specified |
| Packaging | Electropolished 316L, cleaned for semiconductor service | Medical cylinder preparation | General industrial cylinder preparation |
| Primary use | CVD/ALD oxidation chemistry | Anesthesia/analgesia | General oxidation/process gas |
Moisture above approximately 1 ppmv in the oxidizer stream can introduce silanol groups and increase wet etch rate in deposited silicon dioxide. Hydrocarbon residues can form carbon-rich defects and promote gas-phase particle generation. Electropositive metals such as sodium and potassium are mobile in oxide films and shift transistor threshold voltage. These contaminants are not relevant for medical or industrial applications but are direct process-kill parameters for gate oxide and interlayer dielectric deposition. Therefore, the electronic/EL grade designation is not a marketing distinction; it reflects cylinder preparation, analytical testing, and supply-chain controls intended to maintain trace impurity levels from packaging through point of use. Because no universal electronic grade specification exists, the exact limits must be aligned with the particular diffusion, CVD, or ALD reactor and the technology node.
Because the electronic/EL restriction is at trace-contaminant level, replacing an industrial cylinder with an electronic grade cylinder without evaluating downstream purification, line materials, and sampling paths may not deliver the required purity at the tool. Surface adsorption, dead legs, elastomeric O-rings, and inadequate purge cycles can reintroduce moisture and hydrocarbons even when the cylinder gas meets specification. For this reason, qualification is frequently performed with point-of-use analytical sampling, not solely with cylinder certificates. Published data for exact purge volume requirements across cylinder sizes is limited; therefore, gas system qualification is generally based on point-of-use analytical response rather than fixed purge time alone.
In plasma-enhanced chemical vapor deposition and atomic layer deposition, N2O is delivered to the process chamber as a controlled oxygen radical source. Typical delivery flow ranges are process- and chamber-specific, often between 50 and 2,000 sccm for single-wafer or batch tools, with chamber pressure in the rough vacuum regime from 0.5 to 8 Torr. The gas dissociates in the plasma to produce oxygen radicals. Because N2O has a lower bond dissociation rate than molecular oxygen under typical plasma conditions, the radical flux can be moderated more easily, reducing uncontrolled gas-phase oxidation. In silicon oxynitride deposition, the N2O flow ratio to silane or dichlorosilane influences nitrogen incorporation, refractive index, film stress, and wet etch rate. Process engineers monitor refractive index by spectroscopic ellipsometry and film composition by X-ray photoelectron spectroscopy or Fourier transform infrared spectroscopy. Particle adders, metal contamination, or moisture-induced process drift are the primary reasons to specify electronic/EL grade N2O; mass flow controller stability and gas cabinet pressure stability are equally important because fluctuations in N2O flow alter the O:N ratio and therefore film properties. Compared with molecular oxygen, N2O-based oxidation may require higher radio-frequency power or increased residence time to achieve equivalent growth rate; published data for specific film stacks is limited, so tool-level design of experiments is required.
Gas-phase nucleation control in PECVD is particularly sensitive to oxidizer purity when N2O is used with silane. Oxygen and moisture impurities can alter the silane oxidation reaction path and produce particulate SiO2 in the chamber before film deposition, increasing chamber particle counts and requiring more frequent plasma clean cycles. The use of electronic/EL grade N2O with total hydrocarbons below 0.5 ppmv and water below 1 ppmv reduces the concentration of nucleation precursors but does not eliminate the need for periodic chamber seasoning and in situ cleaning. Published data for a specific plasma chamber geometry is limited; qualification is typically performed by measuring particles per wafer pass using a surface particle counter and by monitoring wet etch rate stability across the wafer. In batch LPCVD furnaces, tube-to-tube and across-boat uniformity can be affected by N2O flow distribution. Mass flow controllers may be configured with full-scale ranges of 100, 500, 1,000, and 5,000 sccm depending on chamber volume; calibration with N2O or use of gas-specific correction factors is required because the thermal transport and density differ from nitrogen.
Material compatibility and safety boundaries must be defined before use. Nitrous oxide is not flammable but is a strong oxidizer; contact with oil, grease, organic residues, or reducing gases can create an ignition hazard. Downstream components should be constructed from 316L stainless steel or other materials qualified under ISO 11114-1:2020. Backflow prevention, interlocking purge valves, and pressure relief devices are required in gas distribution lines. Thermal decomposition of N2O can occur at elevated temperatures and may be accelerated by catalytic surfaces; process exhaust lines should be evaluated for maximum allowable temperature and internal cleanliness. Workplace exposure is controlled below the ACGIH TLV-TWA of 50 ppm, and continuous monitoring is used in gas cabinet and valve manifold box locations. Cylinder storage must be separated from reducing agents and combustible materials in accordance with local fire codes and compressed gas regulations. No additional handling procedure should be implemented without reviewing the cylinder valve outlet, fill density, and material compatibility data in the supplier's safety data sheet.
