Hafnium oxide: A thin film dielectric with controllable etch resistance for semiconductor device fabrication

Thin film dielectrics are ubiquitous in the manufacture of electronic devices and are frequently deposited and etched away at various stages of device fabrication. We demonstrate that hafnium oxide (HfO2) thin films grown via atomic layer deposition on silicon and silicon pre-coated with aluminum ox...

Full description

Saved in:
Bibliographic Details
Published in:AIP advances 2023-06, Vol.13 (6)
Main Authors: Wratten, A., Walker, D., Khorani, E., Healy, B. F. M., Grant, N. E., Murphy, J. D.
Format: Article
Language:English
Subjects:
Acid resistance
Aluminum oxide
Annealing
Atomic layer epitaxy
Carrier lifetime
Controllability
Crystallization
Current carriers
Dielectrics
Etching
Hafnium oxide
Hydrofluoric acid
Inspection
Millimeter waves
Semiconductor devices
Silicon substrates
Silicon wafers
Temperature dependence
Thin films
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Thin film dielectrics are ubiquitous in the manufacture of electronic devices and are frequently deposited and etched away at various stages of device fabrication. We demonstrate that hafnium oxide (HfO2) thin films grown via atomic layer deposition on silicon and silicon pre-coated with aluminum oxide (Al2O3) have etch resistance properties, which can be tuned simply by changing the post-deposition annealing temperature. The etching rates of films in hydrofluoric acid (HF) solutions were found to be dependent on annealing temperature, with the etch rate decreasing with increasing temperature. A transition region in the etch rate was identified between 300 and 350 °C, corresponding to the crystallization of the HfO2 films, as identified via x-ray diffraction. HfO2 films deposited directly onto silicon annealed above 350 °C were resistant to 10% HF solutions over the course of several hours. In the case of Si/Al2O3/HfO2 stacks, closer inspection reveals the existence of channels, which reduces the etch resistance of HF acid, as evidenced by tetramethylammonium hydroxide etching of the silicon substrate. Crystallized HfO2 can be used to protect other dielectrics in device processing, and we demonstrate its use in single-sided fabrication of patterned structures of Al2O3, which can control the effective charge-carrier lifetime in silicon wafers for use in modulating THz and mm-wave radiation.
ISSN:2158-3226
2158-3226
DOI:10.1063/5.0144639