ADVANCED TECHNIQUES FOR GLANCING ANGLE DEPOSITION

When a thin film is deposited by physical vapor deposition, with the v apor flux arriving at an oblique angle from the substrate normal, and under conditions of sufficiently limited adatom mobility to create a c olumnar microstructure, the resulting structure is somewhat porous and grows at an angle inclined toward the vapor source. For a given mater ial and set of deposition conditions, there is a fixed relationship be tween the angle of vapor flux incident on the substrate and the inclin ation angle at which the columnar thin film grows. As the porosity of the film is also dependent on the incident flux angle, column growth a ngle and porosity cannot be chosen independently. If a large columnar angle (more parallel to the substrate) is desired, the flux must be de posited at a large oblique angle resulting in a very porous film. Conv ersely, if a near vertical columnar film is desired, the flux must arr ive more perpendicular to the substrate and the resulting film has a t ightly packed, dense microstructure. We present a technique, based on glancing angle deposition, employing substrate motion during depositio n, which allows the columnar growth inclination angle and film density to be controlled independently. With this method, microstructurally c ontrolled materials can be fabricated with three dimensional control o n a 10 nm scale for use in optical, chemical, biological, mechanical, magnetic, and electrical applications. (C) 1998 American Vacuum Societ y.