The very low rate soft std AlGaN etch process
increases the surface roughness by only 0.02 nm.
A new method that can be applied to etch this layer with great accuracy
Atomic Layer Etching (ALE)
Here a fast switching technique is used to alternate between a step
that creates a very specific surface compound with the top layer of atoms
and an etching step which removes this layer of compound
only leaving the underlying atoms untouched.
Through this technique very high control and low damage can be achieved
with repeatable etch rates.
The surface becomes smoother than the original surface
(by 0.3 nm for 30 cycles)
with ICP source
ALE kit (patented)