The Improvement in Dielectric Characteristics and Reliability of Atomic-Layer-Deposited HfO2 Thin Films by In-Situ NH3 Injection

Abstract

The improvements in reliability of atomic layer deposited (ALD) HfO2 thin films by an in-situ NH3 injection were studied. The HfO2 film with the in-situ NH3 injection was physically thinner than the HfO2 film without the NH3 injection although the number of ALD cycles was same. The degradation in dielectric performance by post-deposition annealing at 1000oC was more serious for the in-situ NH3 injected HfO2 film compared to the film without the NH3 injection. However, the leakage current degradation by the constant voltage stress (CVS) was much less for the in-situ NH3 injected HfO2 thin film. XPS analysis showed that the HfO2 film with the in-situ NH3 injection has a higher nitrogen concentration in the film which passivates the bulk traps in HfO2 layer and improves the leakage current degradation by the CVS.