研究目的
To develop a robust and reproducible process for growing fully (100) oriented SiC/Si/SiC/Si multi-stacks using chemical vapor deposition, addressing the challenges of Si heteroepitaxy on 3C-SiC(100) due to lattice mismatch and orientation issues.
研究成果
The study successfully demonstrates a method to grow fully (100) oriented SiC/Si/SiC/Si multi-stacks by roughening the 3C-SiC surface through precursor pulse insertion during cooling. This modification promotes (100) orientation inheritance in Si nucleation, overcoming the typical (110) orientation. High defect densities at interfaces due to lattice mismatch decrease with layer thickness through recombination. Antiphase domains in the SiC seed do not affect Si layer quality. This approach is robust and reproducible, with potential for further optimization to improve crystalline quality and surface smoothness.
研究不足
The surface modification process is sensitive to reactor-specific conditions (e.g., temperature and precursor fluxes during pulse insertion), which may require optimization for different setups. The presence of donut-like features on antiphase boundaries could potentially be minimized but was not fully eliminated in this study. The crystalline quality of the Si layer, while improved, still has defects that could be further enhanced by tuning growth conditions or post-growth annealing.
1：Experimental Design and Method Selection:
The study uses a home-made cold-wall vertical reactor at atmospheric pressure for chemical vapor deposition (CVD). The process involves in situ cleaning of Si(100) wafers under H2, growth of 3C-SiC seed layers via a two-step CVD process (carbonization and epitaxy), surface modification by pulse insertion of precursors during cooling, Si deposition, and subsequent SiC regrowth. The design aims to achieve fully (100) oriented stacks by modifying the SiC surface roughness to influence Si nucleation orientation.
2：Sample Selection and Data Sources:
Si(100) wafers are used as substrates. The 3C-SiC seed layers are grown to 1.8 μm thickness. Samples are characterized at various growth stages for intermediate analysis.
3：8 μm thickness. Samples are characterized at various growth stages for intermediate analysis.
List of Experimental Equipment and Materials:
3. List of Experimental Equipment and Materials: Equipment includes a home-made cold-wall vertical CVD reactor, atomic force microscopy (AFM), secondary electron microscopy (SEM), transmission electron microscopy (TEM) using a Jeol 2100 operating at 200 kV, and X-ray diffraction (XRD). Materials include SiH4, C3H8, H2 gases, and Si(100) wafers.
4：Experimental Procedures and Operational Workflow:
Steps include in situ H2 cleaning, 3C-SiC growth (carbonization at 1165°C, epitaxy at 1350°C), cooling to 1000°C, optional precursor pulse insertion for surface modification, Si deposition at 1000°C, and SiC regrowth. Some samples are removed for intermediate characterization and re-treated under H2 to remove surface oxide before continuing growth.
5：Data Analysis Methods:
Morphological analysis via AFM and SEM; structural characterization via TEM (diffraction contrast and cross-section modes) and XRD; data interpretation focuses on orientation, defect density, and surface morphology.
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