Strem Chemicals offers nearly 50 types of bubblers

7 November 2014

Atomic layer deposition (ALD) is a thin film deposition technique that is based on the sequential use of a gas phase chemical process. It used to be known as Molecular Layering and is often used in microelectronics; the majority of ALD reactions use two chemicals, typically called precursors.

These precursors react with the surface of a material one at a time in a sequential, self-limiting, manner. Through the repeated exposure to separate precursors, a thin film is slowly deposited.

Bubblers are used in the making of CVD/ALD processes and are liquid at room temperature; they are also used in powder form in certain cases. Most precursors are air and/or water sensitive and very flammable or pyrophoric in nature. Nevertheless, they exhibit good thermal stability and are storable for extended periods of time if well packed. For the CVD/ALD process, precursors are generally utilized directly from the package wherein they were supplied in order to avoid their handling issues. For this reason, the package must be considered as a component of the product.

Generally bubblers with internal dip tubes are utilised as a packaging option for liquids, while stainless steel cylinders with the suitable seals and fittings are utilized for gases. Typically, the transfer of liquid precursors into the reaction chamber is performed by bubbling a carrier gas via the container wherein they are stored at or less than room temperature.

Hydrogen is the most commonly used carrier gas; however, nitrogen or other inert gases can serve the purpose in certain cases. The use of catalysts is of paramount importance in delivering reliable methods of Silicon dioxide ALD.

Without catalysts surface reactions leading to the formation of silicon dioxide are generally very slow and only occur at exceptionally high temperatures

The outstanding chemical, electrical, and optical properties of silicon dioxide have made it invaluable in science and technology

The ability to create silicon dioxide nano structures have broaden its applications especially in chemical electro kinetic and biomedical fields in nanotechnology

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http://www.strem.com/

Strem Chemicals UK Ltd

An Independent Distributor of Strem Chemicals Products in the UK and Ireland
Newton Hall
Town Street
Newton
Cambridge, UK CB22 7ZE
Tel: 0845 643 7263 or 01223 873028

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