Multi-scale simulation of epitaxial processes — Linda Jäckel1,2,3, Andreas Zienert1,2,3, Erik E. Lorenz1,2,3, Max Huber1,2,3, Jörg Schuster1,2,3 1 Fraunhofer Institute for Electronic Nano Systems ENAS, Chemnitz, Germany ² Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, Chemnitz, Germany ³ Center for Microtechnologies, Chemnitz University of Technology, Chemnitz, Germany Introduction Epitaxial growth are competitive processes in semiconductor industry Helpful insights for process optimization and transfer through modeling and simulation strategies possible Multi-scale simulations needed to investigate growth on small features Reactor-scale modeling Example: Single-wafer reactor for Si epitaxy Goal: Optimization of single-wafer reactor Si epitaxial growth from DCS (SiH2Cl2) Newly developed chemistry model for low-temperature Si epitaxial growth Process optimization using reactor-scale simulation to identify relevant parameters Result: Reduced wafer rotation speed ω most promising option for variability reduction Si growth rates by wafer rotation speed ω. SiGe growth rate over 100 horizontally oriented wafers. Simplified single-wafer reactor with gas flow velocity magnitudes (color) and velocity vectors (black arrows). Multi-wafer reactor with wafer boat (blue), inlet pipes (orange), inlets (red), outlet (green) and the outer reactor hull (gray). Example: Multi-wafer reactor for SiGe epitaxy Goal: Optimization of complex multi-wafer batch reactor with multiple gas inlets Result: Wafer-to-wafer variability of growth rate due to local cooling near gas inlets more inlets less variability Feature-scale modeling Si film growth with 10x10 nm² size constraint: Atomistic representation (left) and extracted facets (right). Goal: Investigation of epitaxial growth on feature-scale Approach: Kinetic Monte Carlo-based effective attachment model2 Effective growth surface, dependent on temperature, composition, surrounding features Simulation of pattern- and time-dependent local growth rates Facet extraction: Delauney-based Alpha shape extraction with simplical decomposition3 Multi-scale modeling Multi-scale coupling approach combing CFD and KMC. Deposition processes on structured substrates: only feature- scale model alone not sufficient Multi-scale model combing feature-scale and reactor-scale approach is possible4 Implementation in CFD-ACE+ with user defined functions Local effects of global gas flow considered Result: model which fully captures the deposition characteristics for epitaxial growth on small features Si Growth rate as a function of trench width. 1 C. Werner and M. Hierlemann, “Applications of PHOENICS-CVD to epitaxial SiGe polysilicon and silicon dioxide deposition in range of CVD reactors,” PHOENICS Journal, vol. 8, no. 4, pp. 538–552, 1995. 2 R. Chen, W. Choi, A. Schmidt, K.-H. Lee, and Y. Park, “A new kinetic lattice monte carlo modeling framework for the source-drain selective epitaxial growth process,” in 2013 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD). IEEE, Sep. 2013. DOI: 10.1109/sispad.2013.6650561 3 P. G. Goerss and J. F. Jardine, Simplicial homotopy theory. Springer Science & Business Media, 2009. 4 N. Cheimarios, G. Kokkoris, and A. G. Boudouvis, “Multiscale modeling in chemical vapor deposition processes: Coupling reactor scale with feature scale computations,” Chemical Engineering Science, vol. 65, no. 17, pp. 5018–5028, 2010. DOI: 10.1016/j.ces.2010.06.004 This work was funded by the EFRE fund of the European Commission and by funding of the Free State of Saxony of the Federal Republic of Germany (project MOMENTUM, grant number 100358750). Methods Reactor-scale: Computational fluid dynamics using CFD-ACE+ Feature-scale: Inhouse-Code Multi-scale coupling with user defined functions in CFD-ACE+