Molecular-beam epitaxy



 

Molecular beam single crystals. It was invented in the late 1960s at Bell Telephone Laboratories by J. R. Arthur and Alfred Y. Cho.

Method

Molecular beam epitaxy takes place in high vacuum or ultra high vacuum (10−8 epitaxially. However, the slow deposition rates require proportionally better vacuum in order to achieve the same impurity levels as other deposition techniques.

In solid-source MBE, ultra-pure elements such as mean free paths of the beams.

During operation, light-emitting diodes.

In systems where the substrate needs to be cooled, the ultra-high vacuum environment within the growth chamber is maintained by a system of Celsius). However, cryogenic temperatures act as a sink for impurities in the vacuum, and so vacuum levels need to be several orders of magnitude better to deposit films under these conditions. In other systems, the wafers on which the crystals are grown may be mounted on a rotating platter which can be heated to several hundred degrees Celsius during operation.

Molecular beam epitaxy is also used for the deposition of some types of chemical vapor deposition.

ATG instability

ATG (Asaro-Tiller-Grinfeld) instability, formerly known as Grinfeld instability, is an elastic instability often encountered during molecular beam epitaxy. If there is a mismatch between the lattice sizes of the growing film and the supporting crystal, elastic energy will be accumulated in the growing film. At some critical height, the free energy of the film can be lowered if the film breaks into isolated islands, where the tension can be relaxed latterally. The critical height depends on Young moduli, mismatch size, and surface tensions.

Some applications for this instability have been searched, such as the self assembly of quantum dots. This community uses the name of Stranski-Krastanov for ATG.

References

  1. Structural properties of self-organized semiconductor nanostructures

J. Stangl, V. Holý & G. Bauer, Rev. Mod. Phys.76, 725 (2004) (59 pages).

  1. Spontaneous ordering of nanostructures on crystal surfaces, Vitaliy A. Shchukin and Dieter Bimberg,

Rev. Mod. Phys. 71, 001125 (1999) (47 pages)

  1. Jaeger, Richard C. (2002). "Film Deposition", Introduction to Microelectronic Fabrication. Upper Saddle River: Prentice Hall. ISBN 0-201-44494-7. 

See also
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Molecular-beam_epitaxy". A list of authors is available in Wikipedia.