We report on an attempt to suppress the short step bunching (SSB) generated on substrates with a vicinal off-angle during an increase in the temperature of H-2-atmosphere treatment prior to epitaxial growth. The relationship between etching depth and SSB density was investigated by adding SiH4 or C3H8 and varying the H-2 flow rate. We found that etching depth and SSB density decreased when SiH4 was added and the H-2 flow rate was reduced; the SSB density decreased to one-tenth of that obtained under usual conditions. In contrast, the SSB density increased when C3H8 was added, although the etching depth decreased. We discuss differences between adding SiH4 or C3H8 and reducing the H-2 flow rate. We conclude that it is important to not only decrease the etching depth but also inhibit the etching reactions so that SSB generation can be suppressed. (C) 2014 Elsevier B.V. All rights reserved,