Flattening technique of (551) silicon surface using Xe/H₂ plasma

In order to flatten Si(551) surface the thermal annealing in Ar ambience at the atmospheric pressure was performed. The surface roughness of Si(551) is very flat after annealing at 600 °C. It is considered that Si atoms on Si(551) surface easily migrate at lower temperature than Si(100). However because the very roughened spot are locally appeared, the atomically flat silicon surface cannot be obtained on Si(551) yet. Xe/H₂ plasma process is also performed at low temperature less than 600 °C At the H₂ concentration of 10 % and at the process pressure of 266 Pa, Ra of Si(551) surface has a very flat value of 0.068 nm. It is considered that the surface migration of Si atoms on Si(551) surface increasingly progresses because Si(551) surface became activated by Xe/H₂ plasma.