Each specific use of ALD for industry and academic research applications needs to have specific properties for thin film deposited, optimized throughput, as well as optimized costs, etc…
Therefore many different ALD tools and set-up are used and innovative processes using ALD are developed every day. These innovations can come from:
- A modification of the gas carrier system
- A modification of the ALD sequence: from temporal to spatial
- A modification of the ALD set-up to process not only one wafer but many wafers (batch) at the same time
- A modification of the ALD from a “normal” to a “partial” ALD mode for increasing the growth per cycle while keeping the very good conformality
- An adaptation of the ALD process for the atomic scale removing of atoms, Atomic Layer Etching (ALE or ALEt)
- A modification of the plasma source and reactor design
Some of these innovative ALD processes are currently studied by researchers from the GDR framework: development of an ALD process with a Direct Liquid Injection (DLI) of precursors having a low vapor pressure; development of an atmospheric spatial ALD tool with an atmospheric plasma assistance; development of Atomic Layer Etching processes.
The figure below is an illustration of how next generation of SC devices will need to use both ALD and ALE processes. This figure shows a 5 nm GAAFets realized using ALE for etching of trenches and to separate the stack into fins and then afterwards to individual nanowires and using ALD for the conformal deposition of the high k/metal gate stack around nanowire channels.