Quantum transport in sputtered, epitaxial Si/Si1-xGex heterostructures

Radio-frequency magnetron sputter epitaxy was employed for the synthesis of n-type modulation doped Si/Si1-xGex heterostructures. Si channels were grown coherently on sputtered, compositionally graded Si1-xGex buffers of low defect density, and remotely doped with phosphorus by plasma assisted gas phase doping. Magnetotransport measurements on these films revealed Shubnikov-de Haas oscillations in the longitudinal and the integer quantum Hall effect in the transverse magnetoresistance, demonstrating the presence of a two-dimensional electron gas. At T = 1.6 K and sheet densities of 10(12) cm(-2), electron mobilities as high; as 15 800 cm(2)/V s give evidence of the excellent structural and electronic properties achievable by the sputter growth technique. (C) 1995 American Institute of Physics.