Effect of surface NH 3 anneal on the physical and electrical properties of HfO 2 films on Ge substrate

Abstract

Metalorganic-chemical-vapor deposited HfO 2 and TaN was used to fabricate metal-oxide-semiconductor capacitors on germanium substrates. It was demonstrated that a significant improvement in gate leakage current and equivalent oxide thickness (EOT) could be achieved by using surface annealing step in NH 3 ambient before HfO 2 deposition. It was also demonstrated that it was possible to fabricate a capacitor with an EOT of 10.5 Å and a leakage current of 5.02×10 -5 A/cm 2 at i V gate bias. The presence of Ge within the HfO 2 films, which might be due to Ge diffusion at the high temperature used in the chemical vapor deposition process was demonstrated.