Hostname: page-component-77c89778f8-fv566 Total loading time: 0 Render date: 2024-07-16T22:20:46.381Z Has data issue: false hasContentIssue false
  • English
  • Français

Dislocation Interactions And Their Impact On Electrical Properties Of GeSi-Based Heterostructures

Published online by Cambridge University Press:  15 February 2011

S. A. Ringel  and
P. N. Grillot
S. A. Ringel
Affiliation:
DepartInent of Electrical Engineering, The Ohio State University, Columbus, OH 43210, ringel@ee.eng.ohio-state.edu
P. N. Grillot
Affiliation:
Now at Hewlett Packard Optoelectronics, San Jose, CA, 95131, pat_grillot@hp.com
Get access

Abstract

Substantial improvements in the quality of relaxed, heteroepitaxial GeSi layers have occurred in the past few years due to both the development of compositionally-graded buffer layers and to an improved understanding of strain-relaxation in lattice-mismatched epitaxy, which have led to low dislocation densities within these layers. As a result, high performance GeSi devices have been achieved which has fueled yet greater device design flexibility through the use of relaxed GeSi layers over a wider range of alloy compositions and lattice constants. A complete understanding of the properties of all defects that result from strain-relaxation is essential to realize high performance and reliable devices, especially as the lattice-mismatch strain becomes more severe. While the structural properties of dislocations in relaxed GeSi layers have been studied in detail, the electronic properties of these defects and their consequences on the overall electrical properties of relaxed GeSi layers are not well understood. In this paper, we show that for high quality (low dislocation density) relaxed layers, clusters of intrinsic point defects formed by dislocation interaction, rather than the dislocations themselves, now dominate the deep level spectrum. We further show that these defects reduce the electronic material quality for films grown by UHVCVD at low temperatures (650 °C) in comparison to films grown at temperatures > 800 °C even though all films have similarly low threading dislocation densities. Using DLTS, spreading resistance, EBIC and Hall effect measurements, these defects are shown to introduce a low concentration of hole traps from Ev, + 0.05 to Ev + 0.30 eV that compensate and type convert nominally undoped GeSi layers grown at 650 °C to p-type. Annealing studies indicate that these defects anneal out at ∼ 750 – 800 °C(2w, hich is accompanied by conductivity type reversal to ntype, elimination of compensation and increased diffusion length. These observations, in addition to the precise position of each energy level, closely correlate with earlier results on plasticallydeformed bulk Si, suggesting that these defect complexes are of intrinsic origin. We conclude that strain-relaxation in graded heterostructures causes considerable dislocation interaction which introduces point defect complexes associated with dislocations that, in addition to threading dislocation density, must now be considered as an important factor for achieving high electronic quality, relaxed GeSi layers.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 442: Symposium E – Defects in Electronic Materials II , 1996 , 313
Copyright
Copyright © Materials Research Society 1997

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. Hull, R. and Bean, J.C., Crit. Rev. Solid State Mater. Sci. 17, 507 (1992).Google Scholar
2. Fitzgerald, E.A., Mater. Sci. Rep. 7, 87 (1991).Google Scholar
3. Xie, Y.H., Fitzgerald, E.A., Monroe, D., Watson, G.P. and Silverman, P.J., Jpn. J. AppL Phys. 33, 2372 (1994).Google Scholar
4. Fitzgerald, E.A., Xie, Y.H., Monroe, D., Silverman, P.J., Kuo, J.M., Kortan, A.R., Thiel, F.A. and Weir, B.E., J. Vac. Sci. Technol. B 10, 1807 (1992).Google Scholar
5. Grillot, P.N., Ringel, S.A., Fitzgerald, E.A., Watson, G.P. and Xie, Y.H., J. AppL Phys. 77, 676 (1995).Google Scholar
6. Grillot, P.N., Ringel, S.A., Fitzgerald, E.A., Watson, G.P. and Xie, Y.H., J. Appl. Phys. 77, 3248 (1995).Google Scholar
7. Grillot, P.N., Ringel, S.A. and Fitzgerald, E.A., J. Electron. Mater. 25, 1028 (1996).Google Scholar
8. Grillot, P.N., Ringel, S.A., Michel, J. and Fitzgerald, E.A., J. Appl. Phys. 80, 2823 (1996).Google Scholar
9. Grillot, P.N. and Ringel, S.A., Appl. Phys. Lett. 69, 2110 (1996).Google Scholar
10. Souifi, A., Bremond, G., Benyattou, T., Guillot, G., Dutartre, D. and Berbezier, I., J. Vac. Sci Technol. B 10, 2002 (1992).Google Scholar
11. Brighten, J.C., Hawkins, I.D., Peaker, A.R., Kubiak, R.A., Parker, E.H.C. and Whall, T.E., J. Appl. Phys. 76, 4237 (1994).Google Scholar
12. Kimerling, L.C. and Patel, J. R., in VLSI Electronics, ed. By Einspruch, N.G. (Academic, Orlando, 1985), vol. 12, p. 223.Google Scholar
13. Kisielowski-Kemmerich, C., Weber, G. and Alexander, H., J. Electron. Mater. 14, 387 (1985).Google Scholar
14. Alexander, H., in Point and Extended Defects in Semiconductors, edited by Benedek, G., Cavallini, A., and Schroter, W. (Plenum, New York, 1989), p. 51.Google Scholar
15. Ono, H. and Sumino, K., J. Appl. Phys. 57, 287 (1985).Google Scholar
16. Kimerling, L.C., Patel, J.R., Benton, J.L., Freeland, P.E., Inst. Phys. Conf. Ser. 59, 401 (1981).Google Scholar
17. Caldas, M.J., Fazzia, A. and Zunger, A., Appl. Phys. Lett. 45, 671 (1984).Google Scholar
18. Baumann, F.H. and Schroter, W., Philos. Mag. B 48, 55 (1983).Google Scholar