STRAIN-INDUCED INTERFACE ROUGHNESS OF SI1-XCX DELTA-LAYERS ON SI(001)

Ultra thin buried S-C-1-x(x) films (delta layers) of monolayer thickne ss and high carbon concentration (x>0.1) in a Si matrix have been prep ared by molecular beam epitaxy and were structurally characterized by high resolution x-ray diffraction, i.e., measurements of crystal trunc ation rods. The average interface roughness of the delta layers is in the order of 6-10 Angstrom. A larger carbon deposit results in the for mation of thicker Si1-xCx delta layers with lower carbon concentration s and smoother interfaces. This effect is attributed to a reduction of the strain in the delta layer due to the lower carbon concentration. (C) 1997 American Institute of Physics. [S0003-6951(97)00150-2].