Modeling of MOCVD of Si and SiGe
For modeling of Si epitaxy STR offers CVDSim3D sofware. The tool has capabilities for detailed modeling of temperature distribution, flow, and chemical reactions.
Model of Radiative Heat Transfer
- Heat reflection responsible for redirection of the radiant heat to specific parts of the wafer. Both diffuse and specular reflection is considered.
- Absorption by the semitransparent media (upper and lower quartz dome)
- Refraction at the gas/quartz surfaces redirecting radiant heat from the lamps
- High angular discretization model of radiant heat has been implemented for conjugated simulation of the phenomena listed above
Chemical model of silicon deposition from chlorosilanes (DCS, TCS, STC) can be used to simulate epitaxy of single crystalline silicon as well as 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 improve layer thickness and doping uniformity.
Combined, thermal and chemical modeling can be used for optimization of process parameters, gas injection redistribution between inlet zones, flow rate variation, chamber and injector geometry optimization, improving temperature profile, process scaling and transfer.
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.
Global Model of Centura Reactor for Si Epi in CVDSim3D software. Geometry is based on Patents No: US 2014/0263268 A1; US 8,709,156 B2, and Segal et al, Microelectronic Engineering 56 (2001) 93-98
Instant growth rate reflecting gas flow driven non-uniformities. Computed in CVDSim3D software
Computed TCS mass fraction distribution in the middle cross-section of Centura 300 mm reactor cavity
Growth rate vs. TCS concentration. Published in JCG (2008) 310(6) 1112-1117.
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