Thermal stability of multilayer films Pt/Si, W/Si, Mo/Si, and W/C

The thermal stability of multilayer films has been studied by use of small-angle x-ray diffraction. The temperatures at which the periodicities of Pt/Si, W/Si, Mo/Si, and W/C multilayers begin to be worse are 200, 300, 400, 900 0C, respectively. The temperatures of total mixing of Pt/Si, W/Si, Mo/Si, and W/C are 600, 600, 700, and >900 0C, respectively. The periods of Mo/Si and W/Si decrease about 5%, 10%, respectively, after annealing at 400 0C for 0.5 h. The period of W/C increases continuously with the increasing temperatures. After annealing at 1000 0C for 0.5 h the increment of the period of W/C is about 20%. The former may be mainly due to the interfacial reaction between metal and Si and the latter may be due to the expansion of C films in W/C