FORMATION AND CHARACTERIZATION OF SI/COSI2,/SI EPITAXIAL HETEROSTRUCTURES

Si/CoSi2/Si heterostructures have been fabricated by sequentially depositing, in high vacuum, Co and Si onto (001)Si substrate. The growth of an epitaxial CoSi2 layer has been achieved by keeping the Si substrate at 600 degrees C during Co deposition. The Si overlayer has been successively obtained by deposition under different experimental conditions. Elevated substrate temperature has given rise to an epitaxial overlayer, but the high adatom mobility has led to a non-uniform coverage. A more uniform layer has been obtained by room-temperature deposition. The as-deposited amorphous layer has been subsequently crystallized by thermal treatments preserving its uniformity, but the process resulted in a highly defective Si overlayer. Furthermore, a preliminary study on the ion-beam-assisted deposition of Si onto CoSi2/Si heteroepitaxial structures has been performed.