Silicon Semiconductor
Crystal Growth
The Czochralski process is the typical method of crystal growth used to obtain single crystals of semiconductors (e.g., silicon, germanium and gallium arsenide) metals (e.g., palladium, platinum, silver, gold), salts and some man-made (or "lab") gemstones. During the process, for particular crystals, inert and noble gas purging is employed to minimize nitrides, carbonyls and exogenous metal contamination.
Boost your crystal growth process performance with SAES Pure Gas tailored purification solutions.
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Epitaxial Growth
Epitaxy is a specialized hi-tech, thin-film deposition technique. The term epitaxy describes an ordered crystalline growth on a (single-) crystalline substrate. It involves the growth of crystals of one material on the crystal face of another (heteroepitaxy), or the same (homoepitaxy) material. Epitaxy forms a thin film whose material lattice structure and orientation or lattice symmetry is identical to that of the substrate on which it is deposited. Most importantly, if the substrate is a single crystal, then the thin film will also be a single crystal. H2O, O2, CO2, and CH4 are the primary process gas impurities of concern. The use of SAES Pure Gas purification solutions will provide tangible benefits including lower sheet resistance, fewer stacking faults and less junction leakage issues.
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Photolithography
Photolithography is a process used in semiconductor device fabrication to transfer a pattern from a photomask (also called reticle) to the surface of a substrate. Modern Optics components used in lithography and inspection/metrology equipment are constantly pushing the limits of both lenses stack materials and coatings. Lenses, reticles and mirrors are all susceptible to irreversible photo contamination, even if “parts-per-trillion” (PPT) levels of Airborne Molecular Contamination (acid, base, refractory, condensable and volatile organic compounds) in the surrounding purge environment interact with the equipment’s high energy laser light.
SAES Pure Gas has developed several tailored purification solutions for photolithography optics purge gasses (N2, CDA).
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Photomask
Photomask is typically a transparent fused quartz blank covered with a pattern defined with chrome metal as the absorbing film. Photomasks are used at wavelengths of 365 nm, 248 nm, and 193 nm. Photomasks have also been developed for other forms of radiation such as 157 nm, 13.5 nm (EUV), X-ray and electrons and ions, but these require entirely new materials for the substrate and the pattern film.
The narrower the photomask pattern, the more challenging it is to clean. Supercritical CO2 is a new emerging technology that offers several advantages over other wet-cleaning technologies.
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Gate Oxide
The insulating layer that separates the gate and the underlying channel of a metal-oxide-semiconductor field-effect transistor (MOSFET) is heavily affected by process gas purity. The gate terminal is a layer of polysilicon (polycrystalline silicon) placed over the channel, but separated from the channel by a thin insulating layer of what has traditionally been silicon dioxide. More advanced technologies use silicon oxynitride. Diffusion and Annealing processes must be free of all hydrogen and carbon-containing impurities, including H2O, H2, hydrocarbons, CO, and CO2.
SAES Pure Gas’s unique heated-getter and room-temperature purification technologies boost the yield of diffusion and annealing processes. Final device performances will improve in both breakdown voltage and current leakage characteristics.
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Ion Implantation
Ion implantation is a materials engineering process by which ions of a material can be implanted into another solid, thereby changing the physical properties of the solid. The introduction of dopants in a semiconductor is the most common application of ion implantation. Dopant ions such as boron, phosphorus or arsenic are generally created from a gas source, so that the purity of the source must be extremely high. When implanted in a semiconductor, each dopant atom creates a charge carrier in the semiconductor (hole or electron, depending on if it is a p-type or n-type dopant), thus modifying the conductivity of the semiconductor in its vicinity. Gaseous impurities such as O2, H2O, CO, CO2, Hydrocarbons and metals will heavily affect the ion implant process yield.
Leveraging decades of experience in gas purification, SAES Pure Gas has developed tailor-made solutions for ion implantation processes.
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Etch
Gas-phase etching is a fundamental step for several semiconductor processes. It can be either purely chemical (plasma etching), purely physical (ion milling), or combination of both (Reactive Ion Etching, RIE). SAES Pure Gas’s patented purification technologies for corrosive and ion milling carrier gases will improve etching gas purity to well below parts per billions levels.
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Compound Semiconductor
Crystal Growth
The Czochralski process is the typical method of crystal growth used to obtain single crystals of semiconductors (e.g. silicon, germanium and gallium arsenide), metals (e.g. palladium, platinum, silver, gold), salts and some man-made (or "lab") gemstones. During the process, for particular crystals, inert and noble gas purging is employed to minimize nitrides, carbonyls and exogenous metal contamination.
Boost your crystal growth process performance with SAES Pure Gas tailored purification solutions.
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PVD
Plasma-assisted deposition of thin films is extensively adopted in microelectronic circuit manufacturing. Materials deposited include conductors such as tungsten, copper, aluminum, transition-metal silicides, and refractory metals; semiconductors such as gallium arsenide, epitaxial and polycrystalline silicon; and dielectrics such as silicon oxide, silicon nitride, and silicon oxynitride. PVD process gas carriers, typically Ar or other noble gasses, have to be free of hydrocarbons (including CH4), CO, CO2, and N2. Parts-per-billion levels of the aforementioned impurities can generate electromigration failures, reduce grain growth size, and generally changes the electrical film properties.
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CVD
Chemical Vapor Deposition or CVD is a generic name for a group of processes that involve depositing a solid material from a gaseous phase. CVD covers processes such as:
- · Atmospheric Pressure Chemical Vapor Deposition (APCVD)
- · Low Pressure Chemical Vapor Deposition (LPCVD)
- · Metal-Organic Chemical Vapor Deposition (MOCVD) [Link to the MOCVD section]
- · Plasma Assisted Chemical Vapor Deposition (PACVD) or Plasma Enhanced Chemical Vapor Deposition (PECVD)
- · Laser Chemical Vapor Deposition (LCVD)
- · Photochemical Vapor Deposition (PCVD)
- · Chemical Vapor Infiltration (CVI)
- · Chemical Beam Epitaxy (CBE)
In all the processes where gas precursors or carriers are adopted, SAES Pure Gas’s unique and tailored purification solutions can improve yield, reliability and quality.
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MOCVD
Metalorganic chemical vapor deposition or, more generally, metalorganic phase vapor epitaxy (MOVPE), is a chemical vapor deposition method of epitaxial growth of materials, especially semiconductors from the surface reaction of organic compounds and metal hydrides containing the required chemical elements. Formation of the epitaxial layer occurs by final pyrolisis of the constituent chemicals at the substrate surface. III-V MOVPE grown compounds include: GaAs; GaAsP; GaP; InP ; InGaAs; GaN; InGaN and many more.
Metals, oxygenated carbon containing impurities should be reduced as much as possible. See how SAES Pure Gas state-of-the-art purification solutions fit your demanding requirements.
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MBE
Molecular Beam Epitaxy (MBE) is one of a number of methods of thin-film deposition. In solid-source MBE, ultra-pure elements are heated in separate effusion cells until they each slowly begin to evaporate. The evaporated elements then condense on the wafer, where they react with each other, forming a specific semiconductor film. The process takes place in high or ultra-high vacuum. Check how SAES products can help to boost your process yield and quality.
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Optical Fiber
MCVD
Modified Chemical Vapor Deposition soot formation using silicon tetrachloride (SiCl4) or germanium tetrachloride (GeCl4) reaction on Hydrogen burner is affected by process gas purity fluctuations. MCVD process gases impurities can be tackled and controlled at part per trillion levels using MicroTorr product line purification technologies.
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OVD
Optical fiber Outside Vapor Deposition (OVD) lay-down manufacturing process requires ultra high purity specialty gases to form fine soot particles of silica and germania. The glass is formed by flame hydrolysis, a reaction in which silicon tetrachloride or germanium tetrachloride are oxidized by reaction with water (H2O) in an oxyhydrogen flame. Process gas impurities present will generate failure and inconsistency problems during fibers sintering consolidation stage.
MicroTorr purifiers for specialty gases offer unique solutions for OVD part-per-billion process gas purification.
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VAD
Similar to Outside Vapor Deposition, Axial Vapor-phase Deposition (VAD) processes require either silicon tetrachloride or germanium tetrachloride oxidized by reaction with water (H2O) within an oxyhydrogen flame to grow graded-index optical fibers. VAD process gas impurities can be tackled and controlled at part-per-trillion levels using MicroTorr product line purification technologies.
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Other Applications
Analytical Zero Gas
Numerous analytical technologies such as Gas Chromatography, Atmospheric Pressure Ionization Mass Spectrometry (APIMS), and both Oxygen and Moisture Analyzers require precise consistency of carrier and analytical gas quality. Gas impurity loading must be typically controlled down to parts-per-billion levels.
MonoTorr and MicroTorr product lines ensure unique state of the art purification technologies preventing unwanted instrumental background fluctuations.
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Welding and Purging
Welding and purging of ultra-high purity piping systems can benefit using SAES Pure Gas state-of-the-art purification expertise. The FaciliTorr’s unique room temperature and factory regenerable technology ensures consistent and reproducible welding, removing all oxygen containing species from the process gas. In purging applications, it provides fast dry down of UHP gas systems during start up and operation. Learn more about SAES Pure Gas FaciliTorr here.
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Automotive
Analysis of exhaust emissions for research and EPA vehicle qualifications require extremely clean “zero” air for both dilution and analyzer support (calibration and oxidation gases). Besides needing ppb purity for all hydrocarbons, CO and NOX, some applications of the “zero air” must have extremely stable O2 content – a quality in processed air that is often variable but not normally controlled. SAES Pure Gas can provide “sub ppb” solutions for all “zero air” needs.
Learn more about the CAS (Clean Air Supply) purifiers here.
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Sensors
For the challenging gas sensor market, SAES Pure Gas has developed a unique set of Point-of-Use (POU) purifiers to protect gas sensors without affecting their main functionality.
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Beverage
The purity demands of beverage related gases are increasing day to day. Leveraging two decades of gas purification technologies experience, SAES Pure Gas provides state-of-the-art solutions for beverage CO2 purification.
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