Characteristics of High-Crystallinity ZrO2 Thin Films Deposited Using Remote Plasma Atomic Layer Deposition

Abstract

ZrO2 deposition using the plasma-enhanced atomic layer deposition (PEALD) process with a cyclopentadienyl tris(dimethylamino) zirconium (CpZr(NMe2)(3)) precursor is investigated. The effect of deposition temperature and plasma power on ZrO2 thin films' bonding and electrical properties is studied. CpZr(NMe2)(3) is used for the deposition at 100 W and 200-400 degrees C and at 50-1000 W at 300 degrees C. When generating O-2 plasma, Ar gas and O-2 gas are used together to generate more radicals. It is found that CpZr(NMe2)(3)'s PEALD process window is 200-300 degrees C and the film's crystallinity is strongly influenced by deposition temperature and plasma power. In both process conditions, only the tetragonal phase changes. As a result, the ZrO2 film deposited at 50 W and 300 degrees C has the highest dielectric constant. This is due to the higher O radical ratio that corresponds to lower plasma power. A high O radical ratio causes a chemical reaction rather than an ion bombardment.