Single-step reactive ion etching process for device integration of hafnium-zirconium-oxide (HZO)/titanium nitride (TiN) stacks

Research output: Contribution to journalResearch articleContributedpeer-review

Abstract

The integration of new materials such as high-k dielectrics or metals into advanced CMOS gate stacks has led to major developments in plasma etching. The authors present a study which is dedicated to the etching of amorphous hafnium zirconium oxide (HZO) and titanium nitride (TiN) layers with Ar/Cl2 chemistry in one single step. By adjusting the gas ratio and the inductively coupled plasma power, the etching process is shown to have a slow and well controllable etch rate for HZO and TiN. Additionally, a high selectivity between both materials and SiO2 can be achieved. Gate stack etching was successfully demonstrated and transmission electron microscopy-images revealed good anisotropic etching for HZO and TiN with an etch stop in SiO2 without damaging the silicon underneath. The process is further applied for the fabrication of metal-ferroelectric-metal capacitors, here TiN-HZO-TiN, and the feasibility of the chosen material combination is proven by electrical characterization. The strategy of using low temperature plasma-enhanced atomic layer deposition for TiN-deposition and forming gas anneal after structuring leads to high remanent polarization-values.

Details

Original languageEnglish
Article number095025
Number of pages6
JournalSemiconductor science and technology
Volume36
Issue number9
Publication statusPublished - 1 Sept 2021
Peer-reviewedYes

External IDs

Scopus 85113377492
ORCID /0000-0002-4859-4325/work/142253208
ORCID /0000-0003-3814-0378/work/142256089

Keywords