Relationship of HfO2 Material Properties and Transistor Performance

We report on the relationship between the materials science of a HfO
₂
/TiN stack and transistor performance. Atomic layer deposited (ALD) HfO
₂
can be scaled to a physical thickness of 1.2 nm resulting in EOT 1.0 nm. In scaling HfO
₂
the interfacial SiO
₂
layer (IL) is also scaled and the extent of HfO
₂
crystallization is reduced. Reduced HfO
₂
crystallinity is coincident with reduced threshold voltage instability (10 mV) and increased electron mobility (82% Univ. SiO
₂
). For these stable, high mobility devices, we find that HfO
₂
can coordinate N as Hf-N without excessive nitridation of the IL