Effects of remote plasma pre-oxidation of Si substrates on the characteristics of ALD-deposited HfO2 gate dielectrics

Abstract

We investigated the physical and electrical characteristics of a HfO2 /ultrathin SiO2 (∼0.5 nm)Si structure grown by a remote plasma atomic layer deposition (RPALD). The HF -cleaned Si substrate was oxidized by a remote plasma oxidation (RPO) process and yielded a ∼0.5 nm thick SiO2 layer. HfO2 films were deposited on both H-terminated and RPO-treated Si substrates by the RPALD. During HfO2 film deposition, the RPO-treated sample showed more effectively retarded formation of initial Hf silicate layers than the sample on H-terminated Si. RPO treatment also improves electrical properties including hysteresis, effective fixed oxide charge density (Qf,eff) and equivalent oxide thickness (EOT). © 2006 The Electrochemical Society.