There are four main segments in the thin-layer deposition equipment market – atomic layer deposition (ALD), chemical vapor deposition (CVD), epitaxy, and physical vapor deposition (PVD), also known as sputtering. Although CVD equipment represents the largest equipment type, ALD represents the fastest growing equipment category.

ALD is a technique capable of depositing a variety of thin film materials from the vapor phase. As device requirements push toward smaller and more spatially demanding structures, ALD has demonstrated potential advantages over alternative deposition methods, such CVD and PVD due to its conformality and control over materials thickness and composition. These desirable characteristics originate from the cyclic, self-saturating nature of ALD processes [1].

‪Layers are formed during reaction cycles by alternately pulsing precursors and reactants and purging with inert gas in between each pulse. Each atomic layer formed by this sequential process is a result of saturated surface-controlled reactions. For example, a metal precursor pulse of trimethylaluminum (Al(CH3)3) followed by an oxygen reactant pulse (H2O vapor) results in the formation of a layer of aluminum oxide, a metal oxide compound that can be used as a high-k dielectric.

Building devices atom by atom enables very precise control over the process. Because the ALD process is self-limiting, it results in films with a precise thickness and conformality, even over varied surface topographies. It can be applied to produce different oxides, nitrides or other compounds. ALD provides excellent surface control and can produce thin, uniform and pinhole-free films over large areas by single or tailored multiple layer deposition. Nanolaminates or stacked layers of different materials can also be produced, in a straightforward manner, in the ALD reactor. ​

According to new report by Global Industry Analysts, Inc., the global market for thin layer deposition equipment in semiconductor applications is projected to reach US$13.6 billion by 2020, driven by expanding electronics industry and parallel growth in demand for semiconductor solutions.

In terms of R&D, metal ALD has been challenging because of lack of suitable chemistry and nucleation problems. The development of processes for platinum group metals was a success but need for good industrial processes for many other metals still exists. Metal sulfides are old ALD materials and in industrial use in electroluminescent display production but ALD of selenides and tellurides has been much less studied. The need of chalcogenides in phase change materials and development of alkyl silyl precursors for selenium and tellurium has improved the situation. There is still a need to develop new ALD processes for microelectronics, low-k materials, 2D materials and oxides for transparent TFTs, according to Markku Leskelä, University of Helsinki, Finland.

In addition to applications in microelectronics there are many emerging areas where ALD has been introduced. One important area is energy technology materials. ALD films are used in silicon solar cells as passivation layers and they are extensively studied in many other areas such as dye sensitized solar cells, lithium ion batteries, supercapacitors and fuel cells. Indicative for these and many other applications is the use of known – mostly oxide –processes for protection. Li ion batteries make an exception and new materials and processes have been developed for lithium compounds. Research is also underway to adapt ALD processes to high-throughput roll-to-roll production for printed/flexible electronics.

Key players in the ALD deposition arena include Applied Materials Inc., ASM International N.V., Jusung Engineering Co. Ltd., Lam Research Corporation, Oxford Instruments, Picosun, Tokyo Electron Limited, ULVAC Technologies Inc., Ultratech/Cambridge Nanotech and Veeco Instruments Inc., among others.

The American Vacuum Society hosts an annual conference on Atomic Layer Deposition dedicated to the science and technology of atomic layer controlled deposition of thin films.



Suggested additional reading

Atomic layer deposition goes mainstream in 22nm logic technologies

Successful industrialization of high-density 3D integrated silicon capacitors for ultra-miniaturized electronic components

Particle Atomic Layer Deposition

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ALD tools evolve with industry needs

07/13/2017  Veeco Instruments (Veeco) recently announced that Veeco CNT -- formerly known as Ultratech/Cambridge Nanotech -- shipped its 500th Atomic Layer Deposition (ALD) system to the North Carolina State University.

New prospects for universal memory -- high speed of RAM and the capacity of flash

06/16/2017  Thin films created at MIPT could be the basis for future development of ReRAM.

Lam Research introduces dielectric atomic layer etching capability for advanced logic

09/07/2016  Lam Research Corp., an advanced manufacturer of semiconductor equipment, today announced that it is expanding its atomic layer etching (ALE) portfolio with the addition of ALE capability on its Flex dielectric etch systems.

Lam Research enables next-generation memory with industry's first ALD process for low-fluorine tungsten fill

08/09/2016  Lam Research Corp. (NASDAQ: LRCX), an advanced manufacturer of semiconductor equipment, today introduced an atomic layer deposition (ALD) process for depositing low-fluorine-content tungsten films, the latest addition to its ALTUS family of products.

Ultratech Cambridge Nanotech forms research collaboration with Northeastern University

05/17/2016  Ultratech, Inc. announced the formation of a research collaboration with Professor Thomas J. Webster, Ph.D. at Northeastern University, to study the use of nano-materials produced via ALD for medical applications.

Samco increases local sales staff for North American, European and Asian locations

04/14/2016  Samco, a Japan-based semiconductor process equipment developer and manufacturer, is employing around 20 more people at its locations in North America, China, Taiwan and Singapore, as well as its subsidiary Samco-UCP in Liechtenstein.

Molecular-scale ALD discovery could have industrial-sized impact

03/31/2016  In the world of nano-scale technology, where work is conducted at the atomic level, even the smallest changes can have an enormous impact. And a new discovery by a University of Alberta materials engineering researchers has caught the attention of electronics industry leaders looking for more efficient manufacturing processes.

Stanford researchers advance area selective ALD to develop more energy efficient electronics

01/12/2016  Stanford University researchers sponsored by Semiconductor Research Corporation (SRC) have developed a new area selective atomic layer deposition (ALD) process that promises to accelerate the manufacturing of higher performing, more energy efficient semiconductors.

CVD Source Materials

12/17/2015  Reaction materials for chemical vapor deposition are typically delivered into the chamber in a gaseous form. The source materials can be gases or liquids.

Chemical Vapor Deposition

12/11/2015  Chemical vapor deposition (CVD) is used to produce high-purity thin films.

Atomic Layer Deposition

12/11/2015  ALD is a technique capable of depositing a variety of thin film materials from the vapor phase.

Improving the reliability of dry vacuum pumps in high-k ALD processes

02/10/2015  Design features that contributed most to the improved performance include increased rotational speed, integrated rotor sleeves, and increased purge injection temperature.