THE INFLUENCE OF THERMAL-PROCESSING ON STRUCTURAL AND ELECTRICAL-PROPERTIES OF WXSI1-X SI MULTILAYERS/

Thermal stability of WxSi1-x/Si multilayers (MLs) with x varying from 1 to 0.11 is studied by TEM and LAXS. The structure of the prepared sa mples is amorphous. Doping of W sublayers with silicon affects the int erdiffusion process as well as the crystallization in these sublayers. We investigated these two processes (which have a detrimental influen ce on e.g. X-ray mirror stability) by annealing our samples at 400-deg rees-C for 40 min. The structural changes were monitored by resistance measurement in the temperature range of 1.5-300 K. A correlation betw een structural and electrical characteristics was found, which is base d on the comparison between three different R(T) curves. It is shown i n our paper that the R(T) curve of a ML lies between the R(T) curves o f two extreme types of single layers. The first single layer is the an alogue of a fully intermixed ML and the second one represents a parall el connection of all conductive sublayers. Thus, a simple resistance m easurement can give additional information about the quality of interf aces. We claim that in MLs with ultrathin sublayers the reported highe st thermal stability of the amorphous mixture W0.72Si0.28 cannot be ut ilized because interdiffusion dominates over crystallization so that t he superlattice structure is not retained.