The use of ALD in industry and academic research requires specific processes to optimize the properties of the deposited layers, optimize production yields, optimize costs, etc.
There is, therefore, a wide variety of ALD methods available at present; And new innovations are presented constantly. The different innovations can come from:
- The modification of precursor injection systems
- The modification of the ALD sequence: temporal vs. spatial (SALD)
- The modification of the number of substrates that can be processed at one time (multiplate vs. monoplate system for example)
- The modification of the process to have a mix between CVD and ALD to improve the speed of filing while maintaining the extremely conformal nature of ALD films
- The adaptation of the process to go from depositing a layer atom by atom, to instead removing a layer atom by atom, i.e. the Atomic Layer Etching process (ALE or ALEt)
- The modification of the plasma source and its design for PEALD processes
As part of the GDR, this working group proposes to monitor (technology watch) and participate actively in the development of innovative ALD processes. Three innovations are currently under study: the use of a direct liquid injection (DLI) system for precursors with low vapor pressures; the development of an atmospheric spatial process with or without plasma assistance, and the development of Atomic Layer Etching processes involving the joint use with the ALD, which will make it possible to realize the future transistors as illustrated via the TEM figure below of a transistor 5 nm GAAFETs by IMB and Samsung. Indeed the realization of the trenches between the Fin was done via an ALE process, while the high k/Metal Gate stack required the use of ALD to have ultra conformal deposits.
Cross-section TEM : 5nm GAAFETs - IBM, Samsung and Globalfoundries (Source IBM)
David Munoz-Rojas, LMGP
Christophe Vallée, LTM