Editing Aluminium oxide (section)

===Electrical insulation===
Aluminium oxide is an electrical [[insulator (electricity)|insulator]] used as a substrate ([[silicon on sapphire]]) for [[integrated circuits]],<ref>{{cite book |last1=Butterfield |first1=Andrew |last2=Szymanski |first2=John |year=2018 |title=Dictionary of Electronics and Electrical Engineering |publisher=Oxford University Press |url=https://books.google.com/books?id=UV9gDwAAQBAJ&dq=Aluminium+oxide+is+an+electrical+insulator+used+as+a+substrate+for+integrated+circuits&pg=PT922 |access-date=Sep 7, 2024 |isbn=9780198725725}}</ref> but also as a [[quantum tunneling|tunnel barrier]] for the fabrication of [[superconducting]] devices such as [[single-electron transistor]]s, superconducting quantum interference devices ([[SQUID]]s) and [[Superconducting quantum computing|superconducting qubits]].<ref>{{cite web |url=https://www.preciseceramic.com/blog/why-aluminum-oxide-is-used-in-tools.html |title=Why Aluminum Oxide is Used in Tools? |date=Jan 31, 2024 |last=Ross |first=Lisa |website=Advanced Ceramic Materials |access-date=Sep 7, 2024}}</ref><ref>{{cite web |url=https://phys.org/news/2021-09-materials-superconducting-qubits.html |title=Materials for superconducting qubits |first=Thamarasee |last=Jeewandara |date=Sep 2, 2021 |website=Phys |access-date=Sep 7, 2024}}</ref>

For its application as an electrical insulator in integrated circuits, where the conformal growth of a thin film is a prerequisite and the preferred growth mode is [[atomic layer deposition]], Al<sub>2</sub>O<sub>3</sub> films can be prepared by the chemical exchange between [[trimethylaluminium]] (Al(CH<sub>3</sub>)<sub>3</sub>) and H<sub>2</sub>O:<ref>{{Cite journal|author=Higashi GS, Fleming |title= Sequential surface chemical reaction limited growth of high quality Al<sub>2</sub>O<sub>3</sub> dielectrics |journal=Appl. Phys. Lett.|volume=55 |issue= 19|pages=1963–65 |year=1989 |doi=10.1063/1.102337|bibcode = 1989ApPhL..55.1963H }}</ref>

:2 Al(CH<sub>3</sub>)<sub>3</sub> + 3 H<sub>2</sub>O → Al<sub>2</sub>O<sub>3</sub> + 6 CH<sub>4</sub>

H<sub>2</sub>O in the above reaction can be replaced by [[ozone]] (O<sub>3</sub>) as the active oxidant and the following reaction then takes place:<ref>{{Cite journal|author1=Kim JB |author2=Kwon DR |author3=Chakrabarti K |author4=Lee Chongmu |author5=Oh KY |author6=Lee JH |title= Improvement in Al<sub>2</sub>O<sub>3</sub> dielectric behavior by using ozone as an oxidant for the atomic layer deposition technique
| journal=J. Appl. Phys. |volume=92 |issue= 11| pages=6739–42 |year=2002 |doi=10.1063/1.1515951|bibcode = 2002JAP....92.6739K }}</ref><ref>{{Cite journal|author1=Kim, Jaebum |author2=Chakrabarti, Kuntal |author3=Lee, Jinho |author4=Oh, Ki-Young |author5=Lee, Chongmu |title= Effects of ozone as an oxygen source on the properties of the Al<sub>2</sub>O<sub>3</sub> thin films prepared by atomic layer deposition |journal=Mater Chem Phys |volume=78 |issue= 3| pages=733–38 |year=2003 |doi=10.1016/S0254-0584(02)00375-9}}</ref>

:2 Al(CH<sub>3</sub>)<sub>3</sub> + O<sub>3</sub> → Al<sub>2</sub>O<sub>3</sub> + 3 C<sub>2</sub>H<sub>6</sub>

The Al<sub>2</sub>O<sub>3</sub> films prepared using O<sub>3</sub> show 10–100 times lower leakage current density compared with those prepared by H<sub>2</sub>O.

Aluminium oxide, being a dielectric with relatively large [[band gap]], is used as an insulating barrier in [[capacitors]].<ref name="Belkin">{{cite journal |last1=Belkin |first1=A. |last2=Bezryadin |first2=A. |last3=Hendren |first3=L. |last4=Hubler |first4=A. |title=Recovery of Alumina Nanocapacitors after High Voltage Breakdown |journal=Scientific Reports |date=20 April 2017 |volume=7 |issue=1 |pages=932 |doi=10.1038/s41598-017-01007-9|pmid=28428625 |pmc=5430567 |bibcode=2017NatSR...7..932B }}</ref>