Topological Alignment of NLCS Using Nanoscale Metallic Grooves

Liquid crystal on silicon (LCoS) devices have been exploiting the ever-diminishing CMOS silicon process, which is pushing towards 45nm dimensions. Consequently, such fine metallic structures are bound to influence the alignment of the liquid crystal material. To illustrate this, a number of 1D metal patterns with differing mark-to-space ratio were fabricated using an Electron-Beam exposure technique. The results confirmed Dwight Berreman's topological alignment theory regarding the pitch of the surface topography and how this influences the quality of the planar alignment. Patterns with a metal to spacing ratio of 1:1 were shown to yield higher contrast ratios and hence better planar alignment. Such findings could be useful for developing non-intrusive alignment methods for nanoscale LCoS devices