Atomically controlled processing for Ge CVD epitaxial growth

The concept of atomically controlled processing for group IV semiconductors is based on atomic-order surface reaction control. This approach is especially important for the epitaxial deposition of very thin (nm) layers. Here, the existences of Ge oxide in the CVD reactor resulting from former Ge deposition and hydrogen termination of the wafer surface is impacting the epitaxial growth essentially. Therefore the evaporation of Ge oxide is suppressed by Si coating the reactor before wafer loading and/or Si capping after Ge growth and/or very low temperature SiH4 treatment after wafer loading. By the use of Si0.5Ge0.5 buffer layer, hydrogen termination of the surface is reduced. As a result, nm-order thick Ge epitaxial growth with very short incubation period and the suppression of surface roughness generation is realized.