Abstract

Optical scattering from a defect-etched semiconductor sample is used to characterize dislocations in material. It is shown that when the sample is illuminated normally with a He–Ne (λ = 6328-Å)laser beam reflection pattern can be used to identify the shapes of the etch pits and hence the directions of the dislocation propagation. The integrated light flux scattered by the illuminated sample, normalized by the incident is shown to be proportional to the dislocation density. This principle is applied in two ways to dislocations at the sample surface. In one case the defect-etched sample is scanned under a light beam, the scattered flux is collected by an integrating sphere and measured. In the second case the defect-sample is illuminated with incoherent light of a broad angular spectrum, and a photographic transparency produced which registers an image of the dislocation density distribution of the original sample. These methods for counting dislocations, mapping dislocation distribution, and measuring average dislocation density of the sample are discussed.

© 1988 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. H. E. Bennett, J. O. Porteus, “Relation Between Roughness and Specular Reflectance at Normal Incidence,” J. Opt. Soc. Am. 51, 123 (1961).
    [CrossRef]
  2. A. L. Wertheimer, W. L. Wilcock, “Light Scattering Measurements of Particle Distributions,” Appl. Opt. 15, 1616 (1976).
    [CrossRef] [PubMed]
  3. P. Roche, E. Pelletier, “Characterization of Optical Surfaces by Measurement of Scattering Distribution,” Appl. Opt. 23, 3561 (1984).
    [CrossRef] [PubMed]
  4. B. L. Sopori, “A New Defect Etch for Polycrystalline Silicon,” J. Electrochem. Soc. 131, 667 (1984).
    [CrossRef]
  5. B. L. Sopori, “The Principle of Dislocation Analysis by Coherent Optical Scattering from a Defect-Etched Surface,” J. Electrochem. Soc. 135, 2601 (1988).
    [CrossRef]
  6. E. L. O’Neil, Introduction to Statistical Optics (Addison-Wesley, Reading, MA, 1963), Chap. 7.

1988 (1)

B. L. Sopori, “The Principle of Dislocation Analysis by Coherent Optical Scattering from a Defect-Etched Surface,” J. Electrochem. Soc. 135, 2601 (1988).
[CrossRef]

1984 (2)

1976 (1)

1961 (1)

Appl. Opt. (2)

J. Electrochem. Soc. (2)

B. L. Sopori, “A New Defect Etch for Polycrystalline Silicon,” J. Electrochem. Soc. 131, 667 (1984).
[CrossRef]

B. L. Sopori, “The Principle of Dislocation Analysis by Coherent Optical Scattering from a Defect-Etched Surface,” J. Electrochem. Soc. 135, 2601 (1988).
[CrossRef]

J. Opt. Soc. Am. (1)

Other (1)

E. L. O’Neil, Introduction to Statistical Optics (Addison-Wesley, Reading, MA, 1963), Chap. 7.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (15)

Fig. 1
Fig. 1

Different etch pit shapes: (a) circular; (b) elliptical. (c), (d) shapes below the surface for circular and elliptical etch pits.

Fig. 2
Fig. 2

Different spatial distributions of etch pits: (a) nearly uniform dislocation tangles; (b) forming groups of etch pits.

Fig. 3
Fig. 3

Reflection pattern (a) from a region with circular etch pits (b). (c) A high magnification photograph showing the shape of the etch pits.

Fig. 4
Fig. 4

Schematic of the setup used for photographing the reflection patterns shown in Figs. 3, 5, 6, and 7.

Fig. 5
Fig. 5

Reflection pattern (a) due to a region (b) on a sample with elliptical etch pits. (c) High magnification photograph of the scattering region showing the shape of the etch pits.

Fig. 6
Fig. 6

Reflection pattern representing two groups of elliptical etch pits aligned orthogonal to each other.

Fig. 7
Fig. 7

Reflection pattern representing many different shapes of etch pits (including two orthogonal and elliptical groups).

Fig. 8
Fig. 8

Schematic of the setup for high speed dislocation counting.

Fig. 9
Fig. 9

Measured relationship between the detector signal and dislocation density.

Fig. 10
Fig. 10

Plot of the detector signal obtained by scanning a defect-etched sample in the setup shown in Fig. 9.

Fig. 11
Fig. 11

Dislocation density plot measured across the sample in the same region as the line scan of Fig. 10.

Fig. 12
Fig. 12

Steps involved in using the photographic technique for dislocation mapping: (a) photographic recording; (b) film processing with a γ = 1; (c) scanning the transparency under a beam of light.

Fig. 13
Fig. 13

Measured relationship between local transmittance of the film (developed with a γ = 1) and the dislocation density.

Fig. 14
Fig. 14

Comparison of the transmission line scan of the film (a) and the actual dislocation distribution across the same in the corresponding region (b).

Fig. 15
Fig. 15

(a) Y-modulated image of the dislocation distribution in a sample obtained by scanning a transparency made by the procedure discussed in the text; (b) defect-etched sample.

Equations (5)

Equations on this page are rendered with MathJax. Learn more.

R = R d + R s ,
R d = θ ( except θ = 0 ) R ( θ ) d θ .
R d = constant ( n d · a ) ,
R d = constant · [ 1 - exp ( - n d · a ) ] .
T ( x i , y i ) = [ I ( x o , y o ) · t ] γ constant .

Metrics