Structural and phase transformations in C/Si multilayers during annealing

The structural evolution of a C/Si periodical multilayers is studied by small-angle X-ray diffraction and cross-section transmission electron microscopy. Mixed zones 0.6–0.65 nm thick with different densities are detected at the C/Si and Si/C interfaces in the initial state. The effect of annealing on the thickness, the density, and the phase composition of the layers and the mixed zones is investigated in the temperature range 300–1050$^\circ$C. Two stages of changing the multilayer composition period upon heating are found. The period increases as the temperature increases up to 700$^\circ$C and then decreases. The fracture of the composition begins in the silicon layers, where pores and cubic 3C-SiC nanocrystals form at 900$^\circ$C. The fracture of the layered structure of the composition is completed at $T >$ 1000$^\circ$C.