Atomically controlled CVD processing for doping of Si-based group IV semiconductors

The concept of atomically controlled processing for group IV semiconductors is shown based on atomic-order surface reaction control in Si-based CVD epitaxial growth. Si or Si_1-xGe_x epitaxial growth on N, P or C atomic layer formed on Si(100) or Si_1-xGe_x (100) surface, is achieved at temperatures below 500 °C. In the Si _0.5Ge_0.5 epitaxial layer, a N doping dose of 6x10 ¹⁴ cm^-2 is confined within an about 1.5 nm thick region and the confined N atoms in Si_1-xGe_x preferentially form Si-N bonds. In Si cap layer growth on the P atomic layer formed on Si _1-xGe_x(100) with the P atom amount below about 4x10 ¹⁴ cm^-2 using Si₂H₆ instead of SiH₄, the incorporated P atoms are almost confined within the 1 nm region around the heterointerface. Heavy C atomic-layer doping suppresses strain relaxation as well as intermixing between Si and Ge at the nm-order thick Si_1-xGe_x/Si heterointerface. These results open the way to atomically controlled processing for ULSIs.