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Volume 5, Issue 5 Res. Rev. J Mat. Sci. 2017
ISSN: 2321-6212 Advanced Materials 2017
September 07-08, 2017
September 07-08, 2017 | Edinburgh, Scotland
Advanced materials & Processing
11th International Conference on
Atomic layer deposition routes to monolithic integration of crystalline oxides on semiconductors
John G. Ekerdt, Shen Hu, Edward L. Lin, Pei-Yu Chen, Agham Posdadas and Alexander A. Demkov
Univerisity of Texas at Austin, USA
The semiconductor industry faces new challenges in the sub-10 nm era as scaling will no longer dominate performance
improvement. New materials provide opportunity to improve performance with minimal architectural overhaul. For example,
high-mobility channels of Ge and III-V semiconductors can provide both lower power consumption and faster computing speeds.
In certain applications significant advantages are gained by monolithic integration of the oxides directly on the substrates that
will host other devices/components. Perovskite oxides offer a wide range of properties from high-k to multiferroic affording the
device designer a suite of possibilities, and are particularly important due to their common structure and lattice-matching with
common semiconductors. The gallium nitride device applications will require a dielectric to passivate the nitride surface. Atomic
layer deposition (ALD) allows for growth of perovskite oxides and rare earth oxides in a chemical deposition process that is scalable
and manufacturable. It is possible to grow crystalline perovskites directly on Ge(001) by ALD. Using this approach we have been
able to deposit STO, BaTiO3, SrHfO3, Sr(HfTi)O 3, and SrZrO3 directly on Ge(001). We will discuss the growth and properties of
the perovskite layers directly on Ge(001), and will discuss the interface chemistry and structure that likely controls the interfacial
reactions that allow for crystalline film formation. It is also possible to grow crystalline rare earth oxides directly on GaN(0001) by
ALD. We report approaches to growing crystalline, hexagonal and cubic Er2O3 on wurtzitic gallium nitride, GaN (0001). As with
growth of perovskites on Si and Ge, atomically-thin intermetallic compounds comprised of Group 1 or 2 elements and Group 13-15
elements to facilitate wetting and direct the crystalline growth, in this case the [111] growth direction of the oxides on GaN (0001).
This talk will describe the growth, structures and properties of crystalline oxides grown by ALD.
Biography
John G. Ekerdt is Associate Dean for Research in Engineering and the Dick Rothwell Endowed Chair in Chemical Engineering at the University of Texas at Austin.
He has more than 300 refereed publications, two books and three book chapters, and seven U.S. patents. He has supervised 48 Ph.D. and 8 M.S. students. Current
research interests focus on the surface, growth and materials chemistry of metal, dielectric and perovskite films and nanostructures. The work seeks to: 1) develop
and understand the reactions and chemistry that control nucleation and growth of films and nanostructures, and 2) understand the properties of these materials and
relate the properties to structure, bonding and growth.
John G. Ekerdt et al., Res. Rev. J Mat. Sci. 2017, 5:5
DOI: 10.4172/2321-6212-C1-005
HAADF STEM images showing the interface of
BaTiO3 (BTO) (a), SrZrO3 (SZO) (b), SrHfO3
(SHO) (c) and SrHf0.55Ti0.45O3 (SHTO) (d) films
grown by ALD on Ge (001) substrates. White arrows
mark the position of a single layer Ge surface step.
Structural models below each image illustrate the
interface structure in particular showing the change
in periodicity of the Ge (001) substrate surface
and the location of the Ba (or Sr) atomic columns
between the Ge dimers. S. Hu et al., J. Chem.
Phys.146, 052817 (2017).