Channel release
Beginner
The step that eats away the in-between layers of a nanosheet stack, leaving the silicon ribbons hanging like bridges.
Novice
Removing the silicon-germanium layers with an etch that attacks them and barely touches silicon, so the silicon nanosheets are left suspended between source and drain, ready for the gate to wrap around them.
Expert
Highly selective, isotropic SiGe-to-Si etch after dummy-gate removal. Wet etches risk sheet collapse by capillary forces; hot HCl adds thermal budget (600–760 °C); remote-plasma dry etches avoid both. The gate stack is then deposited around every sheet by ALD.
Explained in Fins and nanosheets (Transistors).
See also: Si/SiGe superlattice, Replacement metal gate.