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Sunday, December 21, 2014

#314 Atomic Layer Etching, ALE

Atomic Layer Deposition (ALD) took advanced semiconductor manufacturing by storm only some 15 years ago. The ALD turned out to be the best technique for the deposition of a few nm thick high-k gate dielectrics for the 45 nm technology generation CMOS and beyond (see blog #248). Since then, ALD grew into an important tool in the arsenal of thin-film deposition techniques in semiconductor manufacturing with applications expanding beyond just a high-k dielectric deposition.



The success of ALD as an additive process featuring atomic layer precision was not followed by the equally precise, atomic scale, subtractive process. It is because atomic layer-by -atomic layer removal of the material is technically more challenging then equally precise deposition. In contrast to isotropic, conformal AL deposition process, which is mostly independent of the chemical composition of the substrate (ALD creates its own surface chemistry), AL etching needs to be anisotropic and highly selective. Similarly to ALD, however, to accomplish atomic layer precision of the material removal process the ALE reaction should be self-limiting.


Because of these challenges the Atomic Layer Etching (ALE) is coming to the commercial life only now. It is a noteworthy development as with an ALE process complementing ALD processes,  new possibilities in advance semiconductor nano-manufacturing are opening up.


Posted by Jerzy Ruzyllo at 07:24 PM | Semiconductors | Link is the personal blog of Jerzy Ruzyllo. With over 35 years of experience in academic research and teaching in the area of semiconductor engineering (currently holding position of a Distinguished Professor of Electrical Engineering and Professor of Materials Science and Engineering at Penn State University), he has a unique perspective on the developments in this progress driving technical domain and enjoys blogging about it.

With over 2000 terms defined and explained, Semiconductor Glossary is the most complete reference in the field of semiconductors on the market today.

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