Deposition of hafnium oxide from Hf t -butoxide and nitric oxide

The high- κ stack consisting of an optional nitride interfacial layer and a Hf O2 layer was studied. The result shows that nitride or oxynitride interfacial layers can be controllably formed down to a few angstroms. The growth of both interfacial layers is self-limited. The introduction of nitric oxide with hafnium t -butoxide during the high- κ deposition leads to smaller effective oxide thickness (EOT) and gate leakage current. EOTs below 1.0 nm have been achieved with this combination of sources. The beneficial effect of nitric oxide can be explained in terms of reduced interfacial EOT, reduction of carbon contamination, and possibly a small trace amount of nitrogen incorporation.