Molecular beam epitaxy of SiGe heterostructures using a newly designed Si effusion cell

We demonstrate the usefulness of a newly designed Si effusion cell which can be used at high temperatures up to 1700°C instead of a conventional electron beam evaporator in solid-source Si molecular beam epitaxy. The growth rate ranges from 0.005 to 0.5 Å s−1 at temperatures from 1350 to 1650°C and agrees well with the temperature dependence of the Si vapor pressure. Photoluminescence was observed from a Si/SiGe quantum well grown on a Si substrate using the Si effusion cell. This indicates that the sample has little defects or dislocations which may result in nonradiative recombination centers or deep levels. It is found from photoreflectance and X-ray diffraction measurements that excellent controllability of the growth rate can be realized by using the Si effusion cell.