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Influence of H2 Preconditioning on the Nucleation and Growth of Self-Assembled Germanium Islands on Silicon (001)

Influence of H2 Preconditioning on the Nucleation and Growth of Self-Assembled Germanium Islands on Silicon (001)
Influence of H2 Preconditioning on the Nucleation and Growth of Self-Assembled Germanium Islands on Silicon (001)
Understanding the effects of growth conditions on the process of self-organisation of Ge nanostructures on Si is a key requirement for their practical applications. In this study we investigate the effect of preconditioning with a high-temperature hydrogenation step on the nucleation and subsequent temporal evolution of Ge self-assembled islands on Si (001). Two sets of structures, with and without H2 preconditioning, were grown by low pressure chemical vapour deposition (LPCVD) at 650ºC. Their structural and compositional evolution was characterised by Rutherford backscattering spectrometry (RBS), atomic force microscopy (AFM) and micro-Raman (?Raman) spectroscopy. In the absence ofpreconditioning, we observe the known evolution of self-assembled Ge nanostructures on Si (001), from small islands with a narrow size distribution, to a bimodal size distribution, through to large islands. Surface coverage and island size increase steadily as a function of deposition time. On the H2 preconditioned surface, however, both nucleation rates and surface coverage are greatly increased during the early stages of self-assembly. After the first five seconds, the density of the islands is twice that on the unconditioned surface, and the mean island size is also larger, but the subsequent evolution is much slower than in the case of the unconditioned surface. This retardation correlates with a relatively high measured stress within the islands. Our results demonstrate that standard processes used during growth, like H2 preconditioning, can yield dramatic changes in the uniformity and distribution of Ge nanostructures self-assembled on Si.
R7.10.1-R7.10.6
Dillaway, G.D.M.
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Cowern, N.E.B.
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Xu, L
a758f3f2-c49a-487c-8f40-fc66b56d2c35
McNally, P.J.
1cbe8ff6-b104-4d43-97ef-00aec9f4bfa8
Jeynes, C.
f74a665f-21d9-4f04-9fc8-6f3ebbc74c0f
Mendoza, E.
019f6658-a9a2-425c-acbb-d43f5fdc3747
Ashburn, P.
68cef6b7-205b-47aa-9efb-f1f09f5c1038
Bagnall, D.M.
5d84abc8-77e5-43f7-97cb-e28533f25ef1
Dillaway, G.D.M.
b92f80dd-5dc9-4724-bfcc-ffeddb9a4940
Cowern, N.E.B.
d5f2073f-03d8-42bc-bf2d-e9024c7b15bf
Xu, L
a758f3f2-c49a-487c-8f40-fc66b56d2c35
McNally, P.J.
1cbe8ff6-b104-4d43-97ef-00aec9f4bfa8
Jeynes, C.
f74a665f-21d9-4f04-9fc8-6f3ebbc74c0f
Mendoza, E.
019f6658-a9a2-425c-acbb-d43f5fdc3747
Ashburn, P.
68cef6b7-205b-47aa-9efb-f1f09f5c1038
Bagnall, D.M.
5d84abc8-77e5-43f7-97cb-e28533f25ef1

Dillaway, G.D.M., Cowern, N.E.B., Xu, L, McNally, P.J., Jeynes, C., Mendoza, E., Ashburn, P. and Bagnall, D.M. (2004) Influence of H2 Preconditioning on the Nucleation and Growth of Self-Assembled Germanium Islands on Silicon (001). Mat. Res. Soc. Symp. Proc., 820, R7.10.1-R7.10.6.

Record type: Article

Abstract

Understanding the effects of growth conditions on the process of self-organisation of Ge nanostructures on Si is a key requirement for their practical applications. In this study we investigate the effect of preconditioning with a high-temperature hydrogenation step on the nucleation and subsequent temporal evolution of Ge self-assembled islands on Si (001). Two sets of structures, with and without H2 preconditioning, were grown by low pressure chemical vapour deposition (LPCVD) at 650ºC. Their structural and compositional evolution was characterised by Rutherford backscattering spectrometry (RBS), atomic force microscopy (AFM) and micro-Raman (?Raman) spectroscopy. In the absence ofpreconditioning, we observe the known evolution of self-assembled Ge nanostructures on Si (001), from small islands with a narrow size distribution, to a bimodal size distribution, through to large islands. Surface coverage and island size increase steadily as a function of deposition time. On the H2 preconditioned surface, however, both nucleation rates and surface coverage are greatly increased during the early stages of self-assembly. After the first five seconds, the density of the islands is twice that on the unconditioned surface, and the mean island size is also larger, but the subsequent evolution is much slower than in the case of the unconditioned surface. This retardation correlates with a relatively high measured stress within the islands. Our results demonstrate that standard processes used during growth, like H2 preconditioning, can yield dramatic changes in the uniformity and distribution of Ge nanostructures self-assembled on Si.

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Published date: 2004
Organisations: Nanoelectronics and Nanotechnology

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Local EPrints ID: 264407
URI: https://eprints.soton.ac.uk/id/eprint/264407
PURE UUID: e8f5e8c3-48c9-4a6f-b728-594c9efcfd26

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Date deposited: 13 Aug 2007
Last modified: 18 Jul 2019 15:45

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