Chemical vapor deposition (CVD) is a vacuum deposition method used to produce high quality, high-performance, solid materials. The process is often used in the semiconductor industry to produce thin films.
Epitaxy refers to a type of crystal growth or material deposition in which new crystalline layers are formed with one or more well-defined orientations with respect to the crystalline substrate. The deposited crystalline film is called an epitaxial film or epitaxial layer. The relative orientation(s) of the epitaxial layer to the crystalline substrate is defined in terms of the orientation of the crystal lattice of each material. For epitaxial growth, the new layer must be crystalline and each crystallographic domain of the overlayer must have a well-defined orientation relative to the substrate crystal structure. Amorphous growth or multicrystalline growth with random crystal orientation does not meet this criterion. For most technological applications, single domain epitaxy, which is the growth of an overlayer crystal with one well-defined orientation with respect to the substrate crystal, is preferred.
Pulsed laser deposition (PLD) is a physical vapor deposition (PVD) technique where a high-power pulsed laser beam is focused inside a vacuum chamber to strike a target of the material that is to be deposited. This material is vaporized from the target which deposits it as a thin film on a substrate. This process can occur in ultra high vacuum or in the presence of a background gas, such as oxygen which is commonly used when depositing oxides to fully oxygenate the deposited films.
A thin film is a layer of material ranging from fractions of a nanometer (monolayer) to several micrometers in thickness. The controlled synthesis of materials as thin films is a fundamental step in many applications. A familiar example is the household mirror, which typically has a thin metal coating on the back of a sheet of glass to form a reflective interface. The process of silvering was once commonly used to produce mirrors, while more recently the metal layer is deposited using techniques such as sputtering. Advances in thin film deposition techniques during the 20th century have enabled a wide range of technological breakthroughs in areas such as magnetic recording media, electronic semiconductor devices, Integrated passive devices, LEDs, optical coatings, hard coatings on cutting tools, and for both energy generation and storage. It is also being applied to pharmaceuticals, via thin-film drug delivery. A stack of thin films is called a multilayer.
Metalorganic vapour-phase epitaxy (MOVPE), also known as organometallic vapour-phase epitaxy (OMVPE) or metalorganic chemical vapour deposition (MOCVD), is a chemical vapour deposition method used to produce single- or polycrystalline thin films. It is a process for growing crystalline layers to create complex semiconductor multilayer structures. In contrast to molecular-beam epitaxy (MBE), the growth of crystals is by chemical reaction and not physical deposition. This takes place not in vacuum, but from the gas phase at moderate pressures. As such, this technique is preferred for the formation of devices incorporating thermodynamically metastable alloys, and it has become a major process in the manufacture of optoelectronics, such as Light-emitting diodes. It was invented in 1968 at North American Aviation Science Center by Harold M. Manasevit.
Chemical beam epitaxy (CBE) forms an important class of deposition techniques for semiconductor layer systems, especially III-V semiconductor systems. This form of epitaxial growth is performed in an ultrahigh vacuum system. The reactants are in the form of molecular beams of reactive gases, typically as the hydride or a metalorganic. The term CBE is often used interchangeably with metal-organic molecular beam epitaxy (MOMBE). The nomenclature does differentiate between the two processes, however. When used in the strictest sense, CBE refers to the technique in which both components are obtained from gaseous sources, while MOMBE refers to the technique in which the group III component is obtained from a gaseous source and the group V component from a solid source.
Atomic layer deposition (ALD) is a thin-film deposition technique based on the sequential use of a gas-phase chemical process; it is a subclass of chemical vapour deposition. The majority of ALD reactions use two chemicals called precursors. These precursors react with the surface of a material one at a time in a sequential, self-limiting, manner. A thin film is slowly deposited through repeated exposure to separate precursors. ALD is a key process in fabricating semiconductor devices, and part of the set of tools for synthesising nanomaterials.
Vacuum deposition is a family of processes used to deposit layers of material atom-by-atom or molecule-by-molecule on a solid surface. These processes operate at pressures well below atmospheric pressure. The deposited layers can range from a thickness of one atom up to millimeters, forming freestanding structures. Multiple layers of different materials can be used, for example to form optical coatings. The process can be qualified based on the vapor source; physical vapor deposition uses a liquid or solid source and chemical vapor deposition uses a chemical vapor.
Isobutylgermane (IBGe, Chemical formula: (CH3)2CHCH2GeH3, is an organogermanium compound. It is a colourless, volatile liquid that is used in MOVPE (Metalorganic Vapor Phase Epitaxy) as an alternative to germane. IBGe is used in the deposition of Ge films and Ge-containing thin semiconductor films such as SiGe in strained silicon application, and GeSbTe in NAND Flash applications.
ASM International is a Dutch headquartered multinational corporation that specializes in design, manufacturing, sales and service of semiconductor wafer processing equipment for the fabrication of semiconductor devices. ASM's products products are used by semiconductor manufacturers in front-end wafer processing in their semiconductor fabrication plants. ASM’s technologies include atomic layer deposition, epitaxy, chemical vapor deposition and diffusion.
Combustion chemical vapor deposition (CCVD) is a chemical process by which thin-film coatings are deposited onto substrates in the open atmosphere.
Ion layer gas reaction (ILGAR®) is a non-vacuum, thin-film deposition technique developed and patented by the group of Professor Dr. Christian-Herbert Fischer at the Helmholtz-Zentrum Berlin for materials and energy in Berlin, Germany. It is a sequential and cyclic process that enables the deposition of semiconductor thin films, mainly for photovoltaic applications, specially chalcopyrite absorber layers and buffer layers. The ILGAR technique was awarded as German High Tech Champion 2011 by the Fraunhofer Society.
Silanization of silicon and mica is the coating of these materials with a thin layer of self assembling units.
Tantalum(V) ethoxide is a metalorganic compound with formula Ta2(OC2H5)10, often abbreviated as Ta2(OEt)10. It is a colorless solid that dissolves in some organic solvents but hydrolyzes readily. It is used to prepare films of tantalum(V) oxide.
Atomic layer etching is an emerging technique in semiconductor manufacture, in which a sequence alternating between self-limiting chemical modification steps which affect only the top atomic layers of the wafer, and etching steps which remove only the chemically-modified areas, allows the removal of individual atomic layers. The standard example is etching of silicon by alternating reaction with chlorine and etching with argon ions.
Tuomo Suntola is a Finnish physicist, inventor, and technology leader. He is best known for his pioneering research in materials science, developing the thin film growth technique called atomic layer deposition.
Valentin Borisovich Aleskovsky was a Soviet scientist and administrator known for his pioneering research on surface reactions underpinning the thin film deposition technique that years later became known as Atomic Layer Deposition. He was the rector of Leningrad Technological Institute (1962-75) and of Leningrad State University (1975-1986).
Markku Leskelä is a Finnish chemist and professor emeritus at University of Helsinki, known for his leading research in atomic layer deposition (ALD).
Two dimensional hexagonal boron nitride is a material of comparable structure to graphene with potential applications in e.g. photonics., fuel cells and as a substrate for two-dimensional heterostructures. 2D h-BN is isostructural to graphene, but where graphene is conductive, 2D h-BN is a wide-gap insulator.
Molecular layer deposition (MLD) is a vapour phase thin film deposition technique based on self-limiting surface reactions carried out in a sequential manner. Essentially, MLD resembles the well established technique of atomic layer deposition (ALD) but, whereas ALD is limited to exclusively inorganic coatings, the precursor chemistry in MLD can use small, bifunctional organic molecules as well. This enables, as well as the growth of organic layers in a process similar to polymerization, the linking of both types of building blocks together in a controlled way to build up organic-inorganic hybrid materials.
