Deposition of atomic layers , or atomic layer deposition ; molecular layering ( Eng. atomic layer deposition or Eng. atomic layer epitaxy abbr., ALD; ALE) - technology for applying thin films based on the consistent use of self-limited chemical reactions to accurately control the thickness of the applied layer.
Description
The technology of deposition of atomic layers, originally called “epitaxy of atomic layers”, was proposed by the Finnish physicist Tuomo Suntola in 1974 [1] (for the development of this technology in 2018, he won the Millennium Technology Prize [1] ). This technology is very similar to chemical vapor deposition . The difference is that chemical reactions are used in the technology of deposition of atomic layers, in which precursors react with the surface alternately (sequentially) and do not interact directly (do not touch each other). The separation of the precursors is provided by purging with nitrogen or argon . Since self-limited reactions are used, the total thickness of the layers is determined not by the duration of the reaction, but by the number of cycles, and the thickness of each layer can be controlled with very high accuracy.
The technology of deposition of atomic layers is used to deposit films of several types, including films of various oxides (Al 2 O 3 , TiO 2 , SnO 2 , ZnO, HfO 2 ), nitrides (TiN, TaN, WN, NbN), metals (Ru, Ir, Pt) and sulfides (e.g. ZnS). Unfortunately, there are not yet enough cheap technologies for growing technologically important materials such as Si, Ge, Si 3 N 4 , and some multicomponent oxides.
Notes
- ↑ 1 2 Physicist Tuomo Suntola Became the winner of the prestigious Millenium Technology Prize . Website of the television and radio company Yleisradio Oy . Yle News Service (May 23, 2018). Date of treatment May 25, 2018. Archived May 25, 2018.