[PDF] https://doi.org/10.3952/physics.2025.65.3.5

Open access article / Atviros prieigos straipsnis
 Lith. J. Phys. 65, 162–172 (2025)
 

MECHANICAL STRESS, OPTICAL AND SURFACE PROPERTIES OF HIGH TEMPERATURE ANNEALED HfO2, Sc2O3 AND Al2O3 BINARY MIXTURE THIN FILMS DEPOSITED BY ION BEAM SPUTTERING
 Giedrius Abromavičius
 Optical Coating Laboratory, Center for Physical Sciences and Technology, Savanorių 231, 02300 Vilnius, Lithuania
 Email: giedrius.abromavicius@ftmc.lt

 Received 21 October 2025; revised 15 November 2025; accepted 20 November 2025

High compressive stress is one of the main drawbacks of ion beam sputtered coatings by deteriorating the flatness of optical components. Mixtures of high refractive index metal oxides with SiO2 allow one to increase the laser induced damage threshold of multilayer stacks. Study of optical, surface roughness and stress properties of HfO2–Al2O3, Sc2O3–Al2O3, HfO2–Sc2O3 binary mixtures using a broad range of post-deposition thermal annealing up to 900°C is presented. Admixing Al2O3 in moderate concentrations to HfO2 and Sc2O3 allows one to sustain a low surface roughness, to decrease the extinction of layers during thermal treatment, while obtaining –360…–560 MPa tensile stress after annealing to 500°C, depending on the particular mixture. The obtained data allow one to point out possible candidates – HfO2(56%)–Al2O3(44%), Sc2O3(70%)–Al2O3(30%), HfO2(~70%)–Sc2O3(~30%) – and the 500–600°C annealing temperature range for the design of stress compensated multilayer coatings for the UV spectral range with potentially increased laser induced damage threshold.
Keywords: ion beam sputtering, coating stress, material mixtures, UV range

JONAPLUOŠČIO DULKINIMO BŪDU SUFORMUOTŲ IR ATKAITINTŲ IKI AUKŠTŲ TEMPERATŪRŲ HfO2, Sc2O3 IR Al2O3 MIŠINIŲ SLUOKSNIŲ ĮTEMPIŲ, OPTINIŲ IR PAVIRŠINIŲ SAVYBIŲ TYRIMAS
 Giedrius Abromavičius

Fizinių ir technologijos mokslų centro Optinių dangų laboratorija, Vilnius, Lietuva
 

Dideli vidiniai įtempiai yra vienas didžiausių jonapluoščio dulkinimo būdu suformuotų optinių dangų trūkumų, mažinančių optinių komponentų plokštiškumą. Aukšto lūžio rodiklio metalų oksidų mišiniai su SiO2 leidžia padidinti daugiasluoksnių dangų lazerio indukuotos pažaidos slenkstį. Tyrime pateikiama HfO2-Al2O3, Sc2O3-Al2O3, HfO2-Sc2O3 mišinių sluoksnių įtempių, optinių ir paviršinių savybių analizė, taikant terminį atkaitinimą plačiame temperatūrų ruože – nuo 300 iki 900 °C. Suformavus HfO2 ir Sc2O3 sluoksnius, pasižyminčius vidutinio dydžio Al2O3 frakcijomis, galima išlaikyti žemą pradinį sluoksnių paviršiaus šiurkštumą, mažėjančią ekstinkciją, taikant terminį atkaitinimą iki aukštų temperatūrų. Šie mišiniai taip pat pasižymi –360...–560 MPa tempiamaisiais įtempiais po kaitinimo iki 500 °C. Gauti duomenys leidžia identifikuoti perspektyvius HfO2(56 %)-Al2O3(44 %), Sc2O3(70 %)-Al2O3(30 %), HfO2(~70 %)-Sc2O3(~30 %) mišinius ir 500–600 °C atkaitinimo temperatūrų ruožą, tinkamus daugiasluoksnių UV optinių dangų projektavimui su kompensuotais įtempiais bei potencialiai didesniu lazerinės pažaidos slenksčiu.


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