HfO2 thin film deposited by remote plasma atomic layer deposition method

Abstract

A remote plasma atomic layer deposition (RPALD) method has been applied to grow a HfO2 thin film on a Si substrate. The in-situ XPS measurement showed the presence of a Hf silicate phase at the initial stage of the RPALD process up to 20 cycles and no Hf silicide formed. The initial Hf silicate was amorphous and grew to a thickness of approximately 2 nm. We also carried out a remote plasma oxidation (RPO) and nitridation (RPN) on a Si substrate to suppress initial Hf silicate formation and to improve the interface quality. RPO and RPN processes effectively retarded Hf silicate formation during HfO 2 deposition or after annealing. The RPO-treated and RPN-treated HfO2 films exhibited lower effective fixed oxide charges and equivalent oxide thickness (EOT) than films on H-terminated Si.