BCl/N plasma for advanced non-Si gate patterning

A BN-like film can be deposited from a BCl/N based plasma in a standard etch chamber at temperatures as low as 60°C. Deposition rate can be varied from 10 nm/min to more than 100 nm/min. The film contains hexagonal BN, but is very unlikely to be a stoichiometric BN. It decomposes at elevated temperatures and is water soluble. The latter property makes the post etch clean easy. The film can be used for sidewall passivation during the patterning of advanced non-Si gates. We are presenting as an example the use of BCl/N plasma for patterning of Ge gates. The Ge gate profile is damaged by pure BCl plasma during HfO removal after the gate patterning. However, BCl/N plasma with 10% N preserve the gate profile while removing the high-k.