Effects of Annealing and Ar Ion Bombardment on the Removal of HfO 2 Gate Dielectric

Abstract

A process was investigated to remove HfO 2 gate dielectric film that had been deposited and annealed under various conditions. The etch rate of HfO 2 annealed at 950°C was 0.14 Å/min in 10% HF, but increased up to 90 Å/min after Ar ion bombardment. The crystalline structure of the annealed HfO 2 films collapsed upon bombardment by Ar ions. The amorphization and rarefaction of HfO 2 by Ar ion bombardment were responsible for the dramatic increase of the etch rates. Almost no consumption of the underlying Si substrate was observed after the removal of the HfO 2 dielectric films. © 2004 The Electrochemical Society. All rights reserved.