Hostname: page-component-8448b6f56d-c47g7 Total loading time: 0 Render date: 2024-04-24T11:08:03.554Z Has data issue: false hasContentIssue false

Liberation of Ion Implanted Ge Nanocrystals from a Silicon Dioxide Matrix via Hydrofluoric Acid Vapor Etching

Published online by Cambridge University Press:  15 February 2011

I.D. Sharp
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 Department of Materials Science and Engineering, University of California, Berkeley, CA 94720
Q. Xua
Affiliation:
Department of Materials Science and Engineering, University of California, Berkeley, CA 94720
C. Y. Liao
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 Department of Materials Science and Engineering, University of California, Berkeley, CA 94720
J.W. Ager III
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
J.W. Beeman
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
K.M. Yu
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
D. Zakharov
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
Z. Liliental-Weber
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
E.E. Haller
Affiliation:
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 Department of Materials Science and Engineering, University of California, Berkeley, CA 94720
Get access

Abstract

A method to liberate germanium (Ge) nanocrystals from silicon dioxide (SiO2) thin films by hydrofluoric acid (HF) vapor etching is presented. Multi-energy implantation of mass separated Ge ions into 500-nm-thick wet oxide layers on silicon (Si) substrates followed by thermal annealing produces nanocrystals that are 2 to 8 nm in diameter. Raman spectra exhibit the expected asymmetric line shapes due to the phonon confinement effect, but with a higher peak frequency than predicted. To free the nanocrystals, samples are etched in HF vapor to selectively remove the SiO2 matrix and expose the nanocrystal surfaces. Raman spectra of etched samples display peak frequencies consistent with relief of compressive stress. The liberated nanocrystals show long-term stability under ambient atmospheric conditions. Ge nanocrystals can be removed from etched surfaces using an ultrasonic methanol cleaning procedure. The nanocrystal-containing solution is applied to a TEM grid and the solvent is evaporated. Subsequently obtained electron diffraction patterns confirm that the nanocrystals survive this transfer step. Thus, liberated Ge nanocrystals are expected to be accessible for a wide range of manipulation processes and direct characterization techniques.

Type
Research Article
Copyright
Copyright © Materials Research Society 2003

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. Rebohle, L., Borany, J. von, Fröb, H., and Skorupa, W., Appl. Phys. B 71, 131 (2000)Google Scholar
2. Hanafi, H.I., Tieari, S., and Khan, I., IEEE Trans. Electron Devices 43, 1553 (1996)Google Scholar
3. Takagahara, T. and Takeda, K., Phys. Rev. B 46, 15 578 (1992).Google Scholar
4. Yamamoto, M., Kashikawa, T., Yasue, T., Harima, H., and Kajiyama, K., Thin Solid Films 369, 100 (2000)Google Scholar
5. Skorupa, W., Rebohle, L., and Gebel, T., Appl. Phys. A 76, 1049 (2003)Google Scholar
6. Fujii, M., Hayashi, S., and Yamamoto, K., Jpn. J. Appl. Phys. 30, 687 (1991)Google Scholar
7. Maeda, Y., Tsukamoto, N., Yazawa, Y., Kanemitsu, Y., and Matsumoto, Y., Appl. Phys. Lett. 59, 3168 (1991)Google Scholar
8. Wilcoxon, J.P., Provencio, P.P., and Samara, G.A., Phys. Rev. B 64, 035417 (2001)Google Scholar
9. Haller, E.E., J. Appl. Phys. 77, 2857 (1995)Google Scholar
10. Heinig, K.H., Schmidt, B., Markwitz, A., Grötzschel, R., Strobel, M., and Oswald, S., Nucl. Instrum. Methods B 142, 969 (1999)Google Scholar
11. Oswald, S., Schmidt, B., and Heinig, K.H., Surf. Interface Anal. 29, 249 (2000)Google Scholar
12. Richter, H., Wang, Z.P., and Ley, L., Solid State Commun. 39, 625 (1981)Google Scholar
13. Cerdeira, F., Buchenauer, C.J., Pollak, F.H., and Cardona, M., Phys. Rev. B 5, 580 (1971)Google Scholar