Quantitative Evaluation of an Epitaxial Silicon-Germanium Layer on Silicon

Jie-Yi Yao, Kun-Lin Lin^*, Chiung-Chih Hsu

National Nano Device Laboratories, Taiwan.

DOI: 10.4236/mr.2015.34006                

Abstract

An epitaxial SixGey layer on a silicon substrate was quantitatively evaluated using rocking curve (RC) and reciprocal space map (RSM) obtained by powder X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS) in conjunction with transmission electron microscopy (TEM), and EDS in conjunction with scanning electron microscopy (SEM). To evaluate the relative deviation of the quantitative analysis results obtained by the RC, RSM, SEM/EDS, and TEM/EDS methods, a standard sample comprising a Si0.7602Ge0.2398 layer on a Si substrate was used. The correction factor (K-factor) for each technique was determined using multiple measurements. The average and standard deviation of the atomic fraction of Ge in the Si0.7602Ge0.2398 standard sample, as obtained by the RC, RSM, TEM/EDS, and SEM/EDS methods, were 0.2463 ± 0.0016, 0.2460 ± 0.0015, 0.2350 ± 0.0156, and 0.2433 ± 0.0059, respectively. The correction factors for the RC, RSM, TEM/EDS, and SEM/EDS methods were 0.9740, 0.9740, 1.0206, and 0.9856, respectively. The SixGey layer on a silicon substrate was quantitatively evaluated using the RC, RSM, and EDS/TEM methods. The atomic fraction of Ge in the epitaxial SixGey layer, as evaluated by the RC and RSM methods, was 0.1833 ± 0.0007, 0.1792 ± 0.0001, and 0.1631 ± 0.0105, respectively. After evaluating the results of the atomic fraction of Ge in the epitaxial layer, the error was very small, i.e., less than 3%. Thus, the RC, RSM, TEM/EDS, and SEM/EDS methods are suitable for evaluating the composition of Ge in epitaxial layers. However, the thickness of the epitaxial layer, whether the layer is strained or relaxed, and whether the area detected in the TEM and SEM analyses is consistent must be considered.

Keywords

Silicon-Germanium, Epitaxial Layer, Rocking Curve, Reciprocal Spacing Map, TEM, SEM, EDS

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Ghosh, K., Das, S., Fissel, A., Osten, H.J. and Laha, A. (2013) Epitaxial Gd2O3 on Strained Si1-xGex Layers for Next Generation Complementary Metal Oxide Semiconductor Device Application. Applied Physics Letters, 103, Article ID: 153501. http://dx.doi.org/10.1063/1.4824422
[2]	Elfving, A., Zhao, M., Hansson, G.V. and Ni, W.-X. (2006) Asymmetric Relaxation of SiGe/Si(110) Investigated by High-Resolution X-Ray Diffraction Reciprocal Space Mapping. Applied Physics Letters, 89, Article ID: 181901. http://dx.doi.org/10.1063/1.2364861
[3]	Zheng, S.Q., Rahman, M.M., Kawashima, M., Mori, M., Tambo, T. and Tatsuyama, C. (2004) Influence of UTA-Si Buffer Layers on the Growth of SiGe Layers Analyzed by High Resolution X-Ray Reciprocal Space Map. Journal of Surface Science and Nanotechnology, 2, 256-260. http://dx.doi.org/10.1380/ejssnt.2004.256
[4]	Lieten, R.R., McCallum, J.C. and Johnson, B.C. (2015) Single Crystalline SiGe Layers on Si by Solid Phase Epitaxy. Journal of Crystal Growth 416, 34-40. http://dx.doi.org/10.1016/j.jcrysgro.2015.01.012
[5]	Chaisakul, P., Marris-Morini, D., Isella, G., Chrastina, D., Roux, X.L., Edmond, S., Cassan, E., Coudevylle, J.-R. and Vivien, L. (2011) Ge/SiGe Multiple Quantum Well Photo-Diode with 30 GHz Bandwidth. Applied Physics Letters, 98, Article ID: 131112. http://dx.doi.org/10.1063/1.3574539
[6]	Shim, K.-H., Yang, H.D. and Kil, Y.-H. (2013) Characterization of Reduced Pressure Chemical Vapor Deposited Si0.8Ge0.2/Si Multi-Layers. Materials Science in Semiconductor Processing, 16, 126-130. http://dx.doi.org/10.1016/j.mssp.2012.06.002
[7]	Jang, J.H., Phen, M.S., Siebin, K., Jones, K.S. and Craciun, V. (2009) Observation of Defects Evolution in Strained SiGe Layers during Strain Relaxation. Materials Letters, 263, 289-291. http://dx.doi.org/10.1016/j.matlet.2008.10.031
[8]	Zheng, S.Q., Mori, M., Tambo, T. and Tatsuyama, C. (2007) The Structural Deformations in the Si/SiGe System Induced by Thermal Annealing. Journal of Materials Science, 42, 5312-5317. http://dx.doi.org/10.1007/s10853-006-0901-2
[9]	Zheng, S., Kawashima, M., Mori, M., Tambo, M. and Tatsuyama, T. (2006) Interdiffusion at Si/SiGe Interface Analyzed by High-Resolution X-Ray Diffraction. Thin Solid Layers, 508, 156-159. http://dx.doi.org/10.1016/j.tsf.2005.08.416
[10]	Kasper, E., Burle, N., Escoubas, S., et al. (2012) Strain Relaxation of Metastable SiGe/Si: Investigation with Two Complementary X-Ray Techniques. Journal of Applied Physics, 111, Article ID: 063507. http://dx.doi.org/10.1063/1.3694037
[11]	Kasper, E., Schuh, A., Bauer, G., Hollander, B. and Kibbel, H. (1995) Test of Vegard’s Law in Thin Epitaxial SiGe Layers. Journal of Crystal Growth, 157, 68-72. http://dx.doi.org/10.1016/0022-0248(95)00373-8
[12]	Denton, A.R. and Ashcroft, N.W. (1991) Vegard’s Law. Physical Review A, 43, 3161-3164. http://dx.doi.org/10.1103/PhysRevA.43.3161
[13]	Dismukes, J.P., Ekstrom, L. and Paff, R.J. (1964) Lattice Parameter and Density in Germanium-Silicon Alloys. Journal of Physical Chemistry, 68, 3021-3027. http://dx.doi.org/10.1021/j100792a049
[14]	Zollner, S., Hildreth, J., Liu, R., Zaumseil, P., Weidner, M. and Tillack, B. (2000) Optical Constants and Ellipsometric Thickness Determination of Strained Si1-x Gex:C Layers on Si (100) and Related Heterostructures. Journal of Applied Physics, 88, 4102-4108. http://dx.doi.org/10.1063/1.1308070
[15]	Nia, W.X., Lyutovich, K., Alami, J., Tengstedt, C., Bauer, M. and Kasper E. (2001) X-Ray Reciprocal Space Mapping Studies of Strain Relaxation in Thin SiGe Layers (≤100 nm) Using a Low Temperature Growth Step. Journal of Crystal Growth, 227-228, 756-760. http://dx.doi.org/10.1016/S0022-0248(01)00821-1