Hostname: page-component-5c6d5d7d68-wpx84 Total loading time: 0 Render date: 2024-08-18T13:53:29.345Z Has data issue: false hasContentIssue false
  • English
  • Français

Microscopic Properties of Thin Films: Learning About Point Defects

Published online by Cambridge University Press:  29 November 2013

A. Ourmazd ,
M. Scheffler ,
M. Heinemann  and
J-L. Rouviere
Get access

Extract

Microscopic properties of thin films are often strongly influenced by departures from “perfection.” These can take the form of extended defects such as dislocations, interfacial roughness, or point defects. Direct imaging of extended defects was one of the early contributions of electron microscopy to solid-state science. Since then, the role of extended defects in controlling the fabrication and properties of thin films has been extensively studied and reviewed. Recently, in-situ observation of strain relaxation in thin-film structures has increased our understanding of dislocation kinetics and its effect on properties of thin films.

In this article, we focus on electron microscopic studies of interfacial roughness, the effect of processing on thin films, and the role and properties of intrinsic point defects in solids. Concurrent development of sophisticated theoretical and experimental approaches has substantially facilitated the investigation of point-defect properties. Here, we illustrate how results from theory and experiment can be combined to form a detailed picture of point-defect diffusion in solids, and highlight areas needing increased attention. Microscopic properties of thin films cannot be covered in a single review. For this reason, and because fabrication of semiconducting thin films has reached unprecedented levels of sophistication, we illustrate this article with references to semiconducting materials.

Our main conclusions can be summarized as follows, (a) Thin films of the highest quality are bounded by interfaces that are microscopically rough. Moreover, thin-film interfaces contain roughness on many length scales, each affecting a subset of the physical properties of interest.

Type
Quantitative Analysis of Thin Films
Information
MRS Bulletin , Volume 17 , Issue 12 , December 1992 , pp. 24 - 32
Copyright
Copyright © Materials Research Society 1992

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. For an excellent review see George, A. and Rabier, J., Rev. Physique Appl. 22 (1987) p. 941.CrossRefGoogle Scholar
2.Hull, R.et al., J. Appl. Phys. 70 (1991) p. 2052.CrossRefGoogle Scholar
3.Ourmazd, A., Hull, R., and Tung, R., Materials Science & Technology, A Comprehensive Review, Vol. 4: Electronics Structure & Properties of Semiconductors, edited by Schröter, W. (VCH, Weinheim, 1991).Google Scholar
4.Ourmazd, A., Taylor, D.W., Cunningham, J., and Tu, C.W., Phys. Rev. Lett. 62 (1989) p. 933.CrossRefGoogle Scholar
5.Grant, J., Menendez, J., Pfeiffer, L.N., West, K.W., Molinari, E., and Baroni, S., Appl. Phys. Lett. 59 (1991) p. 2859.CrossRefGoogle Scholar
6.Warwick, C.A., Jan, W.Y., Ourmazd, A., and Harris, T.D., Appl. Phys. Lett. 56 (1990) p. 2666.CrossRefGoogle Scholar
7.Gammon, D., Shanabrook, B.C., and Katzer, D.S., Phys. Rev. Lett. 67 (1991) p. 1547.CrossRefGoogle Scholar
8.Kim, Y., Ourmazd, A., Bode, M., and Feldman, R.D., Phys. Rev. Lett. 63 (1989) p. 636.CrossRefGoogle Scholar
9.Bode, M., Ourmazd, A., Cunningham, J., and Hong, M., Phys. Rev. Lett. 67 (1991) p. 843.CrossRefGoogle Scholar
10.Rouviere, J-L., Kim, Y., Cunningham, J., Rentschler, J.A., Bourret, A., and Ourmazd, A., Phys. Rev. Lett. 68 (1992) p. 2798.CrossRefGoogle Scholar
11.Ourmazd, A., Baumann, F.H., Bode, M., and Kim, Y., Ultramicroscopy 34 (1990) p. 237.CrossRefGoogle Scholar
12.Ourmazd, A., Taylor, D.W., Bode, M., and Kim, Y., Science 246 (1989) p. 1571.CrossRefGoogle Scholar
13.Warwick, C.A. and Kopf, R.F., Appl. Phys. Lett. 60 (1992) p. 386.CrossRefGoogle Scholar
14.MRS Bulletin XVII (6) 1992.Google Scholar
15.Kim, Y., Ourmazd, A., and Feldman, R.D., J. Vac. Sci. Technol. A 8 (1990) p. 1116.CrossRefGoogle Scholar
16.Prokes, S.M., Glembocki, O.J., and Godby, D.J., Appl. Phys. Lett. 60 (1992) p. 1087.CrossRefGoogle Scholar
17.Baumann, F.H.et al., to be published.Google Scholar
18.Chang, L.L. and Koma, A., Appl. Phys. Lett. 29 (1976) p. 138. Also, in the GaAs/Al.4Ga.6As system, the composition profiles measured by chemical mapping are well-fitted by the solution of the linear diffusion equation.CrossRefGoogle Scholar
19.Guido, L.J., Holonyak, N. Jr., Hsieh, K.C., and Baker, J.E., Appl. Phys. Lett. 54 (1989) p. 262.CrossRefGoogle Scholar
20.Tan, T.Y., Gösele, U., and Yu, S., Critical Rev. in Solid State and Mater. Sci. 17 (1991) p. 47.CrossRefGoogle Scholar
21. By the term “reservoir” we mean an outside supply, capable of providing an unlimited number of, for example, atoms to the sample, such that the (free) energy of a defect created in the sample does not depend on the defect concentration. In this sense, the Fermi level is an electron reservoir. See also Reference 42 below.Google Scholar
22.Biernacki, S., Scherz, U., Gillert, A., and Scheffler, M., Mater. Sci. Forum 38–41 (1989) p. 625.Google Scholar
23.Blöchl, P.E.et al. in Physics of Semiconductors, edited by Anastassakis, E.M. and Joannapolos, J.D. (World Scientific, Singapore, 1990), p. 533.Google Scholar
24. Most intrinsic defects can have a slightly higher equilibrium concentration on the GaAs side than on the AlAs in the GaAs/AlAs heterostructure (see References 25 and 37), but this effect is not important here.Google Scholar
25.Scheffler, M. and Dąbrowski, J., Philos. Mag. A 58 (1988) p. 107.CrossRefGoogle Scholar
26.Scheffler, M., Adv. in Solid State Phys. 22 (1982) p. 115.CrossRefGoogle Scholar
27.Schlüter, M., Third Brazilian School of Semiconductor Physics, edited by da Silva, C.E.T. Gonçalves, Oliveira, L.E., and Leite, J.R. (1987) p. 196.Google Scholar
28.Bachelet, G.B., Baraff, G.A., and Schlüter, M., Phys. Rev. B 24 (1981) p. 915.CrossRefGoogle Scholar
29.Baraff, G.A. and Schlüter, M., Phys. Rev. B 33 (1986) p. 7346.CrossRefGoogle Scholar
30.Zhang, S.B. and Northrup, J.E., Phys. Rev. Lett. 67 (1991) p. 2339.CrossRefGoogle Scholar
31.Laasonen, K., Nieminen, R.M., and Puska, M.J., Phys. Rev. B 45 (1992) p. 4122.CrossRefGoogle Scholar
32.Dąbrowski, J. and Scheffler, M., Proc. 16th Int. Conf. on Defects in Semiconductors (ICDS 16), edited by Davies, G., DeLeo, G.G., and Stavola, M. (Trans Tech Publications, Switzerland, 1991), Mater. Sci. Forum 83–87 p. 735.Google Scholar
33.Dąbrowski, J. and Scheffler, M., Phys. Rev. B 40 (1989) p. 10391.CrossRefGoogle Scholar
34.Heinemann, M. and Scheffler, M., unpublished.Google Scholar
35. It is necessary to add two comments: (1) Our approach here is essentially identical with that taken in References 25, 37, and 38. The only difference is that in the previous work, the As-rich environment was defined as As2 and not As4 gas. (2) There is an important difference to the work of Martin et al.39 and Zhang and Northrup.30 These authors argue that the As4 (or As2) chemical potential is outside the experimental reachable range and that the As-rich environment should be defined as that given by an As crystal. Although this is correct for low temperatures, it is not for typical annealing temperatures, where only As gas exists. The arguments of References 30 and 39 over-look the fact that the chemical potential consists of enthalpy and entropy contributions. Because the entropy contribution is treated separately in Equation 5, it is only the enthalpy that should be considered for the discussion of Table I and Figures 7 and 8.Google Scholar
36.Arthur, J.R., J. Phys. Chem. Solids 28 (1967) p. 2257.CrossRefGoogle Scholar
37.Heinemann, M. and Scheffler, M., Appl. Surf. Sci. 56–68 (1992) p. 628.CrossRefGoogle Scholar
38.Scherz, U. and Scheffler, M., Density/Functional Theory of Sp-Bonded Defects in III-V Semiconductors, in Defects in III-V Compounds, edited by Weber, E. (Academic Press, Boston), to be published.Google Scholar
39.Qian, G-X., Martin, R.M., and Chadi, D.J., Phys. Rev. B 38 (1988) p. 7649.CrossRefGoogle Scholar
40.Pandey, K.C., Phys. Rev. Lett. 57 (1986) p. 2287.CrossRefGoogle Scholar
41.Pandey, K.C. and Kaxiras, E., Phys. Lett. Lett. 66 (1991) p. 915.CrossRefGoogle Scholar
42.Deppe, D.G. and Holonyak, N. Jr., J. Appl. Phys. 64 (1988) p. R93.CrossRefGoogle Scholar
43. Our arguments apply to vacancies and to interstitials diffusing by the “kick out” mechanism.20Google Scholar
44.Bliss, D.E.et al., Phys. Rev. B 71 (1992) p. 1699.Google Scholar
45.Gibson, J.M. and MacDonald, M.L., in Characterization of Defects in Materials, edited by Siegel, R.W., Weertman, J.R., and Sinclair, R. (Mater. Res. Soc. Symp. Proc. 82, Pittsburgh, PA, 1987) p. 109.Google Scholar