Correlation Between Optical Properties And Chemical Composition Of Sputter-deposited Germanium Cxide (GeO_x) Films

Journal Article · Tue Mar 18 00:00:00 EDT 2014 · Optical Materials

DOI:https://doi.org/10.1016/j.optmat.2014.02.023· OSTI ID:1158477

Murphy, Neil R. ^[1]; Grant, J. T. ^[2]; Sun, L. ^[3]; Jones, J. G. ^[1]; Jakubiak, R. ^[1]; Shutthanandan, V. ^[4]; Ramana, Chintalapalle V. ^[5]

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1. Wright Patterson Air Force Base (WPAFB), Dayton, OH (United States)
2. Univ. of Dayton, OH (United States)
3. Wright Patterson Air Force Base (WPAFB), Dayton, OH (United States); General Dynamics Information Technology, Dayton, OH (United States)
4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
5. Univ. of Texas, El Paso, TX (United States)

Germanium oxide (GeO_x) films were grown on (1 0 0) Si substrates by reactive Direct-Current (DC) magnetron sputter-deposition using an elemental Ge target. The effects of oxygen gas fraction, Г = O₂/(Ar + O₂), on the deposition rate, structure, chemical composition and optical properties of GeOx films have been investigated. The chemistry of the films exhibits an evolution from pure Ge to mixed Ge + GeO + GeO₂ and then finally to GeO₂ upon increasing Г from 0.00 to 1.00. Grazing incidence X-ray analysis indicates that the GeO_x films grown were amorphous. The optical properties probed by spectroscopic ellipsometry indicate that the effect of Г is significant on the optical constants of the GeO_x films. The measured index of refraction (n) at a wavelength (λ) of 550 nm is 4.67 for films grown without any oxygen, indicating behavior characteristic of semiconducting Ge. The transition from germanium to mixed Ge + GeO + GeO₂ composition is associated with a characteristic decrease in n (λ = 550 nm) to 2.62 and occurs at Г = 0.25. Finally n drops to 1.60 for Г = 0.50–1.00, where the films become GeO₂. A detailed correlation between Г, n, k and stoichiometry in DC sputtered GeO_x films is presented and discussed.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1158477
• Report Number(s): PNNL-SA-103789; 46698; KP1704020
• Journal Information: Optical Materials, Vol. 36, Issue 7; ISSN 0925-3467
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Environmental Molecular Sciences Laboratory