Gas‐Phase and Surface Kinetics of Epitaxial Silicon Carbide Growth Involving Chlorine‐Containing Species

Abstract

A detailed chemical mechanism for the silicon carbide epitaxial growth using light hydrocarbons, silane, and either chlorosilanes and/or HCl as the chlorine source is presented. The mechanism involves 153 gas-phase and 76 surface reactions among 47 gas-phase and 9 surface species, respectively. A comparison with the performances of the standard process using silane-hydrocarbons is presented, and the observed growth rate increase and the disappearing of the homogeneous silicon droplets in gas phase is explained.

Simulation of Gas-Phase Chemistry for Selected Carbon Precursors in Epitaxial Growth of SiC

“…This is in accordance with the findings in the original publication of this model [11]. From experiments it is observed that growth rates are similar for C 3 H 8 and CH 4 , but that the surface morphology is worse for CH 4 (at the same inlet C/Si ratio). It is also known that the morphology becomes worse at higher C/Si ratios (for the same precursor).…”

“…Etching of the deposited layer will move some material further downstream, and thereby flatten out the deposition profile somewhat. It may very well be that, even though silicon limited growth is predicted here, carbon limited growth could occur at the wafer position for CH 4 as precursor, due to etching. Further work is needed to study this phenomenon.…”

“…1. It is seen that using the detailed model, a large difference in carbon deposition is evident between using C 3 H 8 or CH 4 as precursor. The previous model, however, does not predict any large difference between the two precursors -in contrast the results are very similar.…”

“…When looking at species that contribute the most to carbon deposition, the same five species are predicted regardless of the precursor used: C 2 H 2 , CH 3 , CH 4 , CH 2 and C 2 H 4 . Previous studies have looked at concentration profiles of different molecules in the gas-phase close to the surface, and from that conclusions about which species that are important to growth have been drawn.…”

“…In addition, in real growth runs, more parasitic growth is observed in the wafer area when using CH 4 , as compared to other carbon precursors. This could also be explained by the results here; the model predicts a large amount of "extra" carbon in the wafer area that is not matched by the amount of silicon.…”