Topography of obliquely evaporated silicon oxide films and its effect on liquid-crystal orientation

The topography of silicon oxide films deposited at an angle of incidence of either 60° or 83° has been investigated using transmission electron microscopy. Columnar-growth structure arrayed in rowlike order has been detected for films deposited at both angles of incidence. The columns lie in the plane of incidence in both cases. The column angle of inclination from the normal to the substrate is 35° for the 60° deposition and it is 50° for the 83° deposition. The rows are, on the average, perpendicular to the plane of incidence. The ratio of the column width to the column periodicity is 0.70 for the 60° evaporation and is about 0.20-0.25 for films deposited at an angle of incidence of 83°. It is asserted that the topography of films deposited at the two angles is the primary factor determining the directional orientation of liquid crystals on obliquely deposited silicon oxide.