Morphological stability of multilayer film surface during diffusion processes

It is well known that multilayer thin film structures are inherently stressed owing to lattice mismatch between different layers. Similar to other stressed solids, such materials can self-organize a surface shape with mass redistribution to minimize a total energy. However, the morphological stability are very important in fabrication of defect-free microelectronic devices. With developed model, the conditions leading to instability can be examined. Based on Gibbs thermodynamics and linear theory of elasticity, we present an algorithm for deriving a governing equation that gives the amplitude change of surface undulation via surface and volume diffusion. A parametric study of this equation leads to the definition of a critical undulation wavelength which stabilizes the surface.