Microstructure and phonon behavior in W/Si periodic multilayer structures

Abstract

Abstract The crystallinity of the tungsten (W) phase was improved with an increase in the thickness of this layer in the periodic W/Si multilayer structure. Both the α- and β-W phases were grown simultaneously and the contribution of these phases was modified by a change in the thickness of the W layers. For thinner W layers, the thermodynamically metastable β-W phase dominated, and with an increase in thickness, this phase was suppressed and the stable α-W phase became prominent. The crystallite size of these phases was almost linearly proportional to the thickness of the W layers in the multilayers. With the increase in thickness of Si layers in multilayers, Raman scattering showed a decrease in the bond-angle deviation of Si–Si bonding in the amorphous Si phase. The study revealed ordering of Si–Si bonding in the amorphous phase of Si with an increase in thickness of these layers in periodic W/Si multilayers.