Structural characteristics and optical properties of plasma assisted reactive magnetron sputtered dielectric thin films for planar waveguiding applications

S.J. Pearce (Corresponding Author), M.D.B. Charlton, Jussi Hiltunen, J. Puustinen, J. Lappalainen, J.S. Wilkinson

Research output: Contribution to journalArticleScientificpeer-review

19 Citations (Scopus)

Abstract

Thin films of aluminum oxide (Al2O3), tantalum pentoxide (Ta2O5), titanium oxide (TiO2), yttrium oxide (Y2O3) and zirconium oxide (ZrO2) were deposited by plasma assisted reactive dual magnetron sputtering to determine their suitability as a host for a rare earth doped planar waveguide upconversion laser. The effect of deposition parameters such as cathode, plasma power and oxygen gas flows were studied and the operational working points were determined. Both power and lambda control were used to optimize the optical quality of each material. By using lambda control feedback system, the magnetron power fluctuates to sustain a fixed oxygen flow in the target area reducing the compound layer growth on the material and maintaining a healthy deposition rate. The optical properties, structure and crystalline phase of each film were found to be dependent on the process parameters. X-ray diffraction (XRD) analysis revealed that the thin films varied from amorphous to highly crystalline depending on the deposition conditions. X-ray photoelectron spectroscopy (XPS) was utilized for surface compositional analysis revealing that films had varying stoichiometric ratios which are controlled for each material by the deposition parameters chosen. The waveguide loss for the thin film layers was investigated and Ta2O5 was shown to have a slab waveguide loss of ~ 1 dB/cm at both visible and infra-red wavelengths making it ideal for planar waveguide and laser applications. TiO2, Y2O3 and ZrO2 were found to deposit in a highly crystalline phase. Waveguiding in the TiO2 layers was not possible at 633 nm or in the infrared region. The Y2O3 samples gave low loss (2–4 dB/cm) at the 1.3 and 1.5 μm wavelengths but no waveguiding at 633 nm or 833 nm was possible. Atomic force microscopy showed rough surface topography for TiO2, Y2O3 and ZrO2 akin to their crystalline growth with the SEM images confirming the regular crystalline columnar structure for the case of Y2O3 and ZrO2.
Original languageEnglish
Pages (from-to)4930-4939
Number of pages9
JournalSurface and Coatings Technology
Volume206
Issue number23
DOIs
Publication statusPublished - 2012
MoE publication typeA1 Journal article-refereed

Fingerprint

Dielectric films
Optical properties
Crystalline materials
Plasmas
optical properties
Thin films
Electric losses
thin films
waveguides
Planar waveguides
yttrium oxides
laser applications
waveguide lasers
Tantalum oxides
Oxygen
Infrared radiation
oxygen
tantalum
Laser applications
Wavelength

Keywords

  • Amorphous
  • crystalline
  • dielectrics
  • feedback control
  • reactive sputtering
  • thin film deposition

Cite this

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title = "Structural characteristics and optical properties of plasma assisted reactive magnetron sputtered dielectric thin films for planar waveguiding applications",
abstract = "Thin films of aluminum oxide (Al2O3), tantalum pentoxide (Ta2O5), titanium oxide (TiO2), yttrium oxide (Y2O3) and zirconium oxide (ZrO2) were deposited by plasma assisted reactive dual magnetron sputtering to determine their suitability as a host for a rare earth doped planar waveguide upconversion laser. The effect of deposition parameters such as cathode, plasma power and oxygen gas flows were studied and the operational working points were determined. Both power and lambda control were used to optimize the optical quality of each material. By using lambda control feedback system, the magnetron power fluctuates to sustain a fixed oxygen flow in the target area reducing the compound layer growth on the material and maintaining a healthy deposition rate. The optical properties, structure and crystalline phase of each film were found to be dependent on the process parameters. X-ray diffraction (XRD) analysis revealed that the thin films varied from amorphous to highly crystalline depending on the deposition conditions. X-ray photoelectron spectroscopy (XPS) was utilized for surface compositional analysis revealing that films had varying stoichiometric ratios which are controlled for each material by the deposition parameters chosen. The waveguide loss for the thin film layers was investigated and Ta2O5 was shown to have a slab waveguide loss of ~ 1 dB/cm at both visible and infra-red wavelengths making it ideal for planar waveguide and laser applications. TiO2, Y2O3 and ZrO2 were found to deposit in a highly crystalline phase. Waveguiding in the TiO2 layers was not possible at 633 nm or in the infrared region. The Y2O3 samples gave low loss (2–4 dB/cm) at the 1.3 and 1.5 μm wavelengths but no waveguiding at 633 nm or 833 nm was possible. Atomic force microscopy showed rough surface topography for TiO2, Y2O3 and ZrO2 akin to their crystalline growth with the SEM images confirming the regular crystalline columnar structure for the case of Y2O3 and ZrO2.",
keywords = "Amorphous, crystalline, dielectrics, feedback control, reactive sputtering, thin film deposition",
author = "S.J. Pearce and M.D.B. Charlton and Jussi Hiltunen and J. Puustinen and J. Lappalainen and J.S. Wilkinson",
year = "2012",
doi = "10.1016/j.surfcoat.2012.05.110",
language = "English",
volume = "206",
pages = "4930--4939",
journal = "Surface and Coatings Technology",
issn = "0257-8972",
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}

Structural characteristics and optical properties of plasma assisted reactive magnetron sputtered dielectric thin films for planar waveguiding applications. / Pearce, S.J. (Corresponding Author); Charlton, M.D.B.; Hiltunen, Jussi; Puustinen, J.; Lappalainen, J.; Wilkinson, J.S.

In: Surface and Coatings Technology, Vol. 206, No. 23, 2012, p. 4930-4939.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Structural characteristics and optical properties of plasma assisted reactive magnetron sputtered dielectric thin films for planar waveguiding applications

AU - Pearce, S.J.

AU - Charlton, M.D.B.

AU - Hiltunen, Jussi

AU - Puustinen, J.

AU - Lappalainen, J.

AU - Wilkinson, J.S.

PY - 2012

Y1 - 2012

N2 - Thin films of aluminum oxide (Al2O3), tantalum pentoxide (Ta2O5), titanium oxide (TiO2), yttrium oxide (Y2O3) and zirconium oxide (ZrO2) were deposited by plasma assisted reactive dual magnetron sputtering to determine their suitability as a host for a rare earth doped planar waveguide upconversion laser. The effect of deposition parameters such as cathode, plasma power and oxygen gas flows were studied and the operational working points were determined. Both power and lambda control were used to optimize the optical quality of each material. By using lambda control feedback system, the magnetron power fluctuates to sustain a fixed oxygen flow in the target area reducing the compound layer growth on the material and maintaining a healthy deposition rate. The optical properties, structure and crystalline phase of each film were found to be dependent on the process parameters. X-ray diffraction (XRD) analysis revealed that the thin films varied from amorphous to highly crystalline depending on the deposition conditions. X-ray photoelectron spectroscopy (XPS) was utilized for surface compositional analysis revealing that films had varying stoichiometric ratios which are controlled for each material by the deposition parameters chosen. The waveguide loss for the thin film layers was investigated and Ta2O5 was shown to have a slab waveguide loss of ~ 1 dB/cm at both visible and infra-red wavelengths making it ideal for planar waveguide and laser applications. TiO2, Y2O3 and ZrO2 were found to deposit in a highly crystalline phase. Waveguiding in the TiO2 layers was not possible at 633 nm or in the infrared region. The Y2O3 samples gave low loss (2–4 dB/cm) at the 1.3 and 1.5 μm wavelengths but no waveguiding at 633 nm or 833 nm was possible. Atomic force microscopy showed rough surface topography for TiO2, Y2O3 and ZrO2 akin to their crystalline growth with the SEM images confirming the regular crystalline columnar structure for the case of Y2O3 and ZrO2.

AB - Thin films of aluminum oxide (Al2O3), tantalum pentoxide (Ta2O5), titanium oxide (TiO2), yttrium oxide (Y2O3) and zirconium oxide (ZrO2) were deposited by plasma assisted reactive dual magnetron sputtering to determine their suitability as a host for a rare earth doped planar waveguide upconversion laser. The effect of deposition parameters such as cathode, plasma power and oxygen gas flows were studied and the operational working points were determined. Both power and lambda control were used to optimize the optical quality of each material. By using lambda control feedback system, the magnetron power fluctuates to sustain a fixed oxygen flow in the target area reducing the compound layer growth on the material and maintaining a healthy deposition rate. The optical properties, structure and crystalline phase of each film were found to be dependent on the process parameters. X-ray diffraction (XRD) analysis revealed that the thin films varied from amorphous to highly crystalline depending on the deposition conditions. X-ray photoelectron spectroscopy (XPS) was utilized for surface compositional analysis revealing that films had varying stoichiometric ratios which are controlled for each material by the deposition parameters chosen. The waveguide loss for the thin film layers was investigated and Ta2O5 was shown to have a slab waveguide loss of ~ 1 dB/cm at both visible and infra-red wavelengths making it ideal for planar waveguide and laser applications. TiO2, Y2O3 and ZrO2 were found to deposit in a highly crystalline phase. Waveguiding in the TiO2 layers was not possible at 633 nm or in the infrared region. The Y2O3 samples gave low loss (2–4 dB/cm) at the 1.3 and 1.5 μm wavelengths but no waveguiding at 633 nm or 833 nm was possible. Atomic force microscopy showed rough surface topography for TiO2, Y2O3 and ZrO2 akin to their crystalline growth with the SEM images confirming the regular crystalline columnar structure for the case of Y2O3 and ZrO2.

KW - Amorphous

KW - crystalline

KW - dielectrics

KW - feedback control

KW - reactive sputtering

KW - thin film deposition

U2 - 10.1016/j.surfcoat.2012.05.110

DO - 10.1016/j.surfcoat.2012.05.110

M3 - Article

VL - 206

SP - 4930

EP - 4939

JO - Surface and Coatings Technology

JF - Surface and Coatings Technology

SN - 0257-8972

IS - 23

ER -