Modeling of MOCVD of Si and SiGe
For about 20 years STR is developing the model of silicon deposition from chlorosilanes (DCS, TCS, STC). The model can be used to simulate single crystalline silicon and polysilicon deposition. The model can be applied to analyze and improve process parameters and design features of commercial CVD reactors (e.g. Centura EPI, ASM Epsilon) or experimental laboratory equipment. Modeling can be used to analyze the reasons for layer thickness non-uniformity and test different approaches to improve it. Gas injection redistribution between inlet zones, flow rate variation, chamber geometry optimization, improving temperature profile , and other measures can be simulated to find out the effect on deposition rate and layer uniformity.
Simulation can also be useful in developing of new technology. An example of successful use of numerical simulations in the new CVD system development is a cooperation between STR and Bavarian Center for Applied Energy Research [Journal of Crystal Growth (2008) 310(6) 1112-1117]. The system for the epitaxial growth of silicon layers on rectangular, large-area substrates of up to 43 cm x 43 cm was developed. The temperature distribution, the gas flow, and the distribution of growth rates were calculated by STR software. The simulated growth rates are in good agreement with experimental results.
Computed TCS mass fraction distribution in the middle cross-section of Centura 300 mm reactor cavity
Published in JCG (2008) 310(6) 1112-1117. Top: Growth rate vs. TCS concentration.
Epitaxy of SiGe
A model of SiGe epitaxial growth from SiH4-GeH4-H2 with account for specific features of surface kinetic mechanism is developed and verified using a wide range of literature and experimental data. It reproduces the major experimental features of SiGe epitaxial growth and helps to interpret observed effects. With the developed model, an analysis of the process in a production scale reactor was carried out successfully and growth characteristics were improved. The model for SiGe CVD can be used to investigate the effect of recipe on the following characteristics:
- SiGe growth rate
- Layer thicknes non-uniformity
- Ge content
- Ge concentration decay length in a Si capping layer
Si Epitaxy in Trenches
Modeling analysis of Si epitaxy has been the latest addition to our Si-based modeling portfolio. It is based on a multiscale approach that accounts for the transport and chemical reactions both in the reactor and in the trenches. In joint publication with On Semiconductor (*) we describe the mechanism of direct or reverse growth starvation (higher growth rate at the trench top or bottom, respectively) and explain the evolution of the trench shape observed in the experiment. This research work facilitated improvement of the thickness uniformity within the trench and across the wafer with the proper choice of process parameters.
* “Optimization of deposition uniformity during silicon epitaxy in deep trenches“, by Segal, A., Yakovlev, E., Bazarevskiy, D., Talalaev, R., Ziad, H., Genne, J., Koops, G., Meersman, J., De Pestel, F., Tack, M., jointly with ON Semiconductor, Semiconductor Science and Technology (2019)
“Convection-assisted chemical vapor deposition (CoCVD) of silicon on large-area substrates” by Kunz T, Burkert I, Auer R, Lovtsus A, Talalaev R, Makarov Y, Journal of Crystal Growth (2008) 310(6) 1112-1117, DOI: 10.1016/j.jcrysgro.2007.12.027
“Kinetics of SiGe chemical vapor deposition from chloride precursors” by A.A. Lovtsus, A.S. Segal, A.P. Sid’ko, R.A. Talalaev, P. Storck, L. Kadinski, Journal of Crystal Growth, Volume 287, Issue 2 (2006) Pages 446-449
A.S. Segal, A.P. Sid’ko, S.Yu. Karpov, Yu.N. Makarov, in “Semiconductor Silicon 2002 (9th International Symposium)”, Electrochemical Society Proceedings, 2002-2, 567 (2002)
“Quasi-thermodynamic model of SiGe epitaxial growth” by A.S. Segal, S.Yu. Karpov, A.P. Sid’ko, and Yu.N. Makarov, Journal of Crystal Growth, 225, 268 (2001)
A.S. Segal, A.P. Sid’ko, S.Yu. Karpov, and Yu.N. Makarov, in “Fundamental Gas-Phase and Surface Chemistry of Vapor Deposition II/ Process Control, Diagnostics and Modeling in Semiconductor Manufacturing”, Electrochemical Society Proceedings, 2001-13, 229 (2001)
“Comparison of silicon epitaxial growth on the 200- and 300-mm wafers from trichlorosilane in Centura reactors” by A. S. Segal, A. O. Galyukov, A. V. Kondratyev, A. P. Sid’ko, S. Yu. Karpov, Yu. N. Makarov, W. Siebert and P.Storck, Microelectronic Engineering 56 (2001) 93
“Global model of silicon chemical vapor deposition in Centura reactors” by A.S. Segal, A.O. Galyukov, A.V. Kondrat’yev, A.P. Sid?ko, S.Yu. Karpov, Yu.N. Makarov, W. Siebert, P. Storck, S.A. Lowry, Electrochem. Soc. Proc. 2000-13 (2000) 456
A.S.Segal, A.V.Kondratyev et al, Proc. 197th ECS Meeting, Toronto, 2000