Growth of Highly <100>-Oriented Crystalline Silicon Thin-Films on Molybdenum by Pulsed DC-Magnetron Sputtering

摘要

Highly oriented undoped polycrystalline silicon films were grown by pulsed-dc magnetron sputtering on molybdenum coated glass at low temperature (450°C) with high deposition rate (86 nm/min). According to x-ray diffraction analysis and confirmed by transmission electron microscopy the deposited films show a preferential (001) surface normal orientation. We show that growth on Mo proceeds via direct formation of a polycrystalline incubation layer and subsequent vertical overgrowth with lateral grain sizes of up to 450 nm. At the interface between Si and Mo we observe the formation of a Si-rich mixed phase with a Si:Mo ratio close to 2. Hexagonal β-MoSi_2 could be identified as the dominant phase in this intermixed region. Such films may be used as seeding layers for a subsequent low-temperature homoepitaxial Si growth.