Ytterbium precursors for ALD growth applications in the fabrication of advanced optical and electrical devices


12-12-2019
Tris(2,2,6,6-tetramethyl-3,5-heptanedionato)ytterbium(III), 99% :

Ytterbium Amidinate is a new alternative precursor for the ALD Yb doping of fibre lasers and growth of oxide dielectrics.

 

Ytterbium continues to play an important role in the advancement of optical fibres and semiconductor thin film devices.  The output power of fibre lasers has advanced due mainly to the design and fabrication of Ytterbium doped fibres.  Yb-doped silica fibres are the preferred choice for gain medium in high power sources due to their high threshold for optical damage, high glass stability, low optical losses, easy thermal management and high optical efficiencies.1   Yb-doped fibres are typically  prepared by a combination of Modified Chemical Vapor Deposition (MCVD) and a solution doping technique. This process has become time consuming and expensive to make more complex core structures that require several core layer depositions. The next generation of laser fibres will require more control of doping concentration and uniformity while still maintaining low background losses.

Thin films of Ytterbium oxide, Yb2O3, have been successfully grown onto silicon and glass substrates by Atomic Layer Deposition (ALD) for use as oxide dielectrics in semiconductor devices.2   This same ALD technique can be combined with MCVD for fabricating large mode area Yb-doped fibres.  It is reported that a MCVD soot-preform with a porous layer of SiO2 has been successfully coated with Yb2O3 and Al2O3 using the ALD method.  The precursors used were Yb(thd)3 and ozone. The Yb-doped fibre fabricated by this technique showed that the dopants successfully penetrated the full thickness of the soot layer, showed a background attenuation of 20dB/km, demonstrated a uniform longitudinal Yb-doping profile and good laser characteristics with a slope efficiency of 80%.3 The MCVD-ALD fibre also appeared to be more photodarkening resistant.  An integrated ALD-MCVD manufacturing process can potentially allow several core layer deposition/doping cycles without the need to remove the preform from the MCVD system which in turn would enable accurate in-situ doping with significantly reduced fabrication time.

The precursor Yb(thd)3,  Tris(2,2,6,6-tetramethyl-3,5-heptanedionato)ytterbium(III), 99%, is available from Strem as product #70-0100

Strem also offers a new alternative amidinate based Ytterbium precursor for the ALD growth of oxide films and the doping of optical fibers, Tris(N,N’-di-i-propylacetamidinato)ytterbium(III), 99%, product #70-1000.

Amidinate precursors in general have good volatility and reactivity and are thermally stable making them ideal candidates for ALD and CVD processes.
 

Product #70-0100, Tris(2,2,6,6-tetramethyl-3,5-heptanedionato)ytterbium(III), 99% :

Image1

Product #70-1000, Tris(N,N’-di-i-propylacetamidinato)ytterbium(III), 99%:

Image2

 

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References:

  1. J. Opt. Soc. Am. B27(11), B63-B92 (2010).
  2. Applied Surface Science 256 (3) 847-851 (2009).
  3. Optics Express 20 (22) 25085-25095 (2012).

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For over twenty-five years, Strem Chemicals UK has been distributing high quality specialty chemicals, from Strem Chemicals, Inc, in the UK and Ireland. Strem products are used for research and development and commercial scale applications, especially in the pharmaceutical, microelectronics, chemicals and petrochemicals industries.

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