Numerical study of SiC CVD in a vertical cold-wall reactor

The conventional heat and mass transport model is extended to describe silicon cluster formation in the gas phase and is employed for a numerical analysis of SiC chemical vapor deposition in a commercial vertical rotating disc reactor. The model is verified by comparing the computed growth rate with available experimental data. The growth rate is studied as a function of precursor flow rates varied in a wide range of values. It is found that the growth rate is limited by the gas mixture depletion in silicon atoms due to homogeneous nucleation. The secondary phase formation on the growing surface is analyzed. The SiC growth window depending on the precursor flow rates is calculated, and a significant influence of the homogeneous nucleation on the window width is shown. The model results predict that the Si/C ratio on the wafer can considerably differ from that at the reactor inlet.