Abstract
The integration of dissimilar materials is highly desirable for many different types of device applications but often challenging to achieve in practice. The unrivalled imaging capabilities of the aberration-corrected electron microscope enable enhanced insights to be gained into the atomic arrangements across heterostructured interfaces. This paper provides an overview of our recent observations of oxide-semiconductor heterostructures using aberration-corrected high-angle annular-dark-field and large-angle bright-field imaging modes. The perovskite oxides studied include strontium titanate, barium titanate, and strontium hafnate, which were grown on Si(001) and/or Ge(001) substrates using the techniques of molecular-beam epitaxy or atomic-layer deposition. The oxide layers displayed excellent crystallinity and sharp, abrupt interfaces were observed with no sign of any amorphous interfacial layers. The Ge(001) substrate surfaces invariably showed both 1× and 2× periodicity consistent with preservation of the 2 × 1 surface reconstruction following oxide growth. Overall, the results augur well for the future development of functional oxide-based devices integrated on semiconductor substrates.
This is a preview of subscription content, access via your institution.










References
- 1.
S.A. Chambers: Epitaxial growth and properties of doped transition metal and complex oxide films. Adv. Mater. 22, 219 (2010).
- 2.
J.H. Ngai, F.J. Walker, and C.H. Ahn: Correlated oxide physics and electronics. Annu. Rev. Mater. Res. 44, 1 (2014).
- 3.
A.A. Demkov and A.B. Posadas: Integration of Functional Oxides with Semiconductors (Springer-Verlag, New York, 2014).
- 4.
R.A. McKee, F.J. Walker, and M.F. Chisholm: Crystalline oxides on silicon: The first five monolayers. Phys. Rev. Lett. 81, 3014 (1998).
- 5.
A.A. Demkov, P. Ponath, K. Fredrickson, A.B. Posadas, M.D. McDaniel, T.Q. Ngo, and J.G. Ekerdt: Integrated films of transition metal oxides for information technology. Microelectron. Eng. 147, 285 (2015).
- 6.
M. Haider, S. Uhlemann, E. Schwan, H. Rose, B. Kabius, and K. Urban: Electron microscopy image enhanced. Nature 392, 768 (1998).
- 7.
O.L. Krivanek, N. Dellby, and A.R. Lupini: Towards sub-Å electron beams. Ultramicroscopy 78, 1 (1999).
- 8.
M.A. O’Keefe: Seeing atoms with aberration-corrected sub-Ångstrom microscopy. Ultramicroscopy 108, 196 (2008).
- 9.
U. Dahmen, R. Erni, V. Radmilovic, C. Kisielowski, M-D. Rossell, and P. Denes: Background, status and future of the transmission electron aberration-corrected microscope project. Philos. Trans. R. Soc., A 367, 3795 (2009).
- 10.
O.L. Krivanek, M.F. Chisholm, V. Nicolosi, T.J. Pennycook, G.J. Corbin, N. Dellby, M.F. Murfitt, C.S. Own, Z.S. Szilagyi, M.P. Oxley, S.T. Pantelides, and S.J. Pennycook: Atom-by-atom structural and chemical analysis by annular dark-field electron microscopy. Nature 464, 571 (2010).
- 11.
W. Zhou, M.D. Kapetanakis, M.P. Prange, S.T. Pantelides, S.J. Pennycook, and J-C. Idrobo: Direct determination of the chemical bonding of individual impurities in graphene. Phys. Rev. Lett. 109, 206803 (2012).
- 12.
M.D. McDaniel, T.Q. Ngo, S. Hu, A. Posadas, A.A. Demkov, and J.G. Ekerdt: Atomic layer deposition of perovskite oxides and their epitaxial integration with Si, Ge, and other semiconductors. Appl. Phys. Rev. 2, 041301 (2015).
- 13.
G.D. Wilk, R.M. Wallace, and J.M. Anthony: Gate dielectrics: Current status and materials properties considerations. J. Appl. Phys. 89, 5243 (2001).
- 14.
J.W. Reiner, A.M. Kolpak, Y. Segal, K.F. Garrity, S. Ismail-Beigi, C.H. Ahn, and F.J. Walker: Crystalline oxides on silicon. Adv. Mater. 22, 2919 (2010).
- 15.
H. Wu, T. Aoki, A.B. Posadas, A.A. Demkov, and D.J. Smith: Anti-phase boundaries at the SrTiO3/Si(001) interface studied using aberration-corrected scanning transmission electron microscopy. Appl. Phys. Lett. 108, 091605 (2016).
- 16.
P. Ponath, A.B. Posadas, R.C. Hatch, and A.A. Demkov: Preparation of a clean Ge(001) surface using oxygen plasma cleaning. J. Vac. Sci. Technol., B: Microelectron. Nanometer Struct.—Process., Meas., Phenom. 31, 031201 (2013).
- 17.
P. Ponath, K. Fredrickson, A.B. Posadas, Y. Ren, X. Wu, R.K. Vasudevan, M.B. Okatan, S. Jesse, T. Aoki, M.R. McCartney, D.J. Smith, S.V. Kalinin, K. Lai, and A.A. Demkov: Carrier density modulation in a germanium heterostructure by ferroelectric switching. Nat. Commun. 6, 6067 (2015).
- 18.
K. Fredrickson, P. Ponath, A.B. Posadas, M.R. McCartney, T. Aoki, D.J. Smith, and A.A. Demkov: Atomic and electronic structure of the ferroelectric BaTiO3/Ge(001) interface. Appl. Phys. Lett. 104, 242908 (2014).
- 19.
M. McDaniel, T.Q. Ngo, A. Posadas, C. Hu, S. Lu, D.J. Smith, E.T. Yu, A.A. Demkov, and J.G. Ekerdt: A chemical route to monolithic integration of crystalline oxides on semiconductors. Adv. Mater. Interfaces 1, 1400081 (2014).
- 20.
M. McDaniel, C. Hu, S. Lu, T.Q. Ngo, A. Posadas, A. Jiang, D.J. Smith, E.T. Yu, A.A. Demkov, and J.G. Ekerdt: Atomic layer deposition of crystalline SrHfO3 directly on Ge(001) for high-k dielectric applications. Appl. Phys. Lett. 117, 054101 (2015).
- 21.
T. Aoki, J. Lu, M.R. McCartney, and D.J. Smith: Bright-field imaging of compound semiconductors using aberration-corrected scanning transmission electron microscopy. Semicond. Sci. Technol. (2016). doi: https://doi.org/10.1088/0268-1242/31/9/094002.
- 22.
C-L. Jia, S.B. Mi, K. Urban, I. Vrejoiu, M. Alexe, and D. Hesse: Atomic-scale study of electric dipoles near charged and uncharged domain walls in ferroelectric films. Nat. Mater. 7, 57 (2008).
ACKNOWLEDGMENTS
This work has primarily been supported by the Air Force Office of Scientific Research through Grants FA9550-12-10494 and FA9550-14-10090 and the National Science Foundation Award CMMI-1437050. The authors gratefully acknowledge the use of facilities in the John M. Cowley Center for High Resolution Electron Microscopy at Arizona State University.
Author information
Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Smith, D.J., Wu, H., Lu, S. et al. Recent studies of oxide-semiconductor heterostructures using aberration-corrected scanning transmission electron microscopy. Journal of Materials Research 32, 912–920 (2017). https://doi.org/10.1557/jmr.2016.273
Received:
Accepted:
Published:
Issue Date: