Investigation of giant step bunching in 4H-SiC homoepitaxial growth: Proposal of cluster effect model

We have investigated the H2 etching and growth conditions causing giant step bunching (GSB) in 4H-SiC homoepitaxial growth on 8° off-axis substrates by a chemical vapor deposition method and found that GSB does not occur during H2 etching under a wide range of experimental conditions, whereas GSB occurs during epitaxial growth at extremely low or high C/Si ratios, i.e., an excessive supply of SiH4 or C3H8. To explain these results, we have proposed a model taking into account the effect of Si or C cluster formation called "the cluster effect" model. We have shown that the cluster effect model can explain well our experimental result of GSB occurrence or nonoccurrence during etching and homoepitaxial growth of 4H-SiC.