Hostname: page-component-77c89778f8-vsgnj Total loading time: 0 Render date: 2024-07-19T19:03:09.132Z Has data issue: false hasContentIssue false
  • English
  • Français

Tem Characterization of ZnO and AIN/ZnO Thin Films Grown on Sapphire

Published online by Cambridge University Press:  15 February 2011

K. Dovidenko ,
S. Oktyabrsky ,
A. K. Sharma  and
J. Narayan
K. Dovidenko
Affiliation:
Center for Advanced Materials and Smart Structures, Dept. of Materials Science & Engineering., North Carolina State University, Raleigh, NC 27695-7916, kddovide@eos.ncsu.edu.
S. Oktyabrsky
Affiliation:
Center for Advanced Materials and Smart Structures, Dept. of Materials Science & Engineering., North Carolina State University, Raleigh, NC 27695-7916, kddovide@eos.ncsu.edu.
A. K. Sharma
Affiliation:
Center for Advanced Materials and Smart Structures, Dept. of Materials Science & Engineering., North Carolina State University, Raleigh, NC 27695-7916, kddovide@eos.ncsu.edu.
J. Narayan
Affiliation:
Center for Advanced Materials and Smart Structures, Dept. of Materials Science & Engineering., North Carolina State University, Raleigh, NC 27695-7916, kddovide@eos.ncsu.edu.
Get access

Abstract

Thin (~ 250 nm) films of ZnO grown by pulsed laser deposition on basal plane of sapphire were studied by transmission electron microscopy (TEM). Plan-view TEM study proved the films to be single crystal with the following epitaxial relationship with the substrate: (0001)znO || (0001)sap with the 30 30° in-plane rotation - [0110]ZnO || [1210]sap. Dislocations lying mostly in basal plane of ZnO and aligned along both <:1010> and <1120> directions having b=1/3[1120] were found. ZnO films were found to have layered growth morphology contrary to columnar morphology of III-nitrides. Consequently, the threading dislocation density in ZnO films (opposing to the AIN and GaN) drops very fast with the thickness: down to 107cm-2 at ~ 250 nm. The effect of post-annealing (which caused significant improvement in electrical and optical properties) on the microstructure of ZnO films was also studied. Contrary to the atomically sharp and clean interface in the as-deposited films, the post-annealed ZnO/sapphire interface contained reacted layer of 30 - 60 A thickness. The structure of the interlayer was determined to be ZnAl2O4 (spinel). The formation of this single crystal spinel layer did not cause deterioration of the ZnO film structure or properties. We have also explored the possibilities of using ZnO as a buffer for III-nitride growth. The epitaxial AIN films were grown on top of the ZnO layer by pulsed laser deposition. Thin (20 -60 A) interfacial reaction layer (also spinel ZnAm2O4) was observed between AIN and ZnO. Formation of this interlayer is studied in conjunction with the AIN epitaxy and the characteristics of defects and interfaces.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 526: Symposium Y – Advances in Laser Ablation of Materials , 1998 , 311
Copyright
Copyright © Materials Research Society 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Service, R.F, Science, 276, 1997, p. 895 Google Scholar
2. Nishino, J., Ohshio, S., Kamata, K., Mater. Res. Soc. Proc. 363, 1995, p. 219.Google Scholar
3. Wacogne, B., Roe, M.P., Pattinson, T.J., Pannell, C.N., Appl. Phys. Lett., 67, 1674 (1995).Google Scholar
4. Hayamizu, S., Tabata, H., Tanaka, H., Kawai, T., J. Appl. Phys., 80, 1996, p. 787.Google Scholar
5. Vispute, R.D., Talyansky, V., Trajanovic, Z., Choopun, S., Downes, M., Sharma, R.P., Venkatesan, T., Woods, M.C., Lareau, R.T., Jones, K.A., Illiadis, A.A., Appl. Phys. Lett., 70, 1997, p. 2735.Google Scholar
6. Narayan, J., Dovidenko, K., Sharma, A.K., Oktyabrsky, S., J. Appl. Phys., submitted.Google Scholar
7. Muth, J. F., Lee, J.H., Kolbas, R.M., Sharma, A.K., Oktyabrsky, S., Narayan, J., to be published.Google Scholar
8. Sharma, A.K., Dovidenko, K., Oktyabrsky, S., Moxey, D.E., Muth, J.F., Kolbas, R.M., and Narayan, J., submit. to Advances of Laser Ablation of Materials (Mater. Res. Soc. Proc., San Francisco, CA) 1998.Google Scholar
9. Dovidenko, K., Oktyabrsky, S., Narayan, J., Razeghi, M., J. Appl. Physics, 79, 1996, p. 2439.Google Scholar
10. Hirth, J.P., J. Lothe in Theory of dislocations, Krieger Publishing Co., Malabar, Florida, 1992, p. 354.Google Scholar
11. Dovidenko, K., Oktyabrsky, S., Narayan, J., Joshkin, V., Razeghi, M. in Nitride Semiconductors, edited by Ponce, F.A., DenBaars, S.P., Meyer, B.K., Nakamura, S., Strite, S. (Mater. Res. Soc. Proc. 482, Boston, MA 1997).Google Scholar
12. Narayan, J., Tiwari, P., Chen, X., Chowdhary, R., Zheleva, T., Appl. Phys. Lett., 61, 1290 (1992); U.S. Patent 5406123 (April 11, 1995).Google Scholar