Periodic submicrometer structures by sputtering

It is known that glancing angle deposition (GLAD) utilizing extreme self-sh adowing during film growth can produce periodic microstructures on a predef ined seed layer using electron-beam evaporation. This deposition process ha s been applied to the fabrication of periodic arrays of magnetic pillars an d has possible applications in optical devices. Critical to the production of these microstructures is adherence to a narrow angular flux distribution centered at an oblique incidence angle, and optimizing the seed pattern fo r the desired film characteristics. In this article, a low-pressure, long-t hrow collimated GLAD sputter deposition has been used to fabricate submicro meter scale periodic pillar and quasihelical microstructures over a range o f seed separations (e.g., 150, 300, 600, 900, and 1200 mn) and deposition a ngles (82.5 degrees and 86 degrees with respect to the substrate normal). W e have found that for fixed deposition parameters, periodic quasihelical gr owth degenerates into pillars as the seed separation increases, and that th e transitional region over which this degeneration occurs shifts to high se ed separations with increasing flux incidence angles. This and other growth trends are also observed and described using the three-dimensional (3D) ba llistic simulator, 3D-FILMS, which has proven to be successful in simulatin g the growth of aperiodic and periodic GLAD films. The use of sputtering fo r periodic GLAD simplifies the process control, and should enable depositio n of a broader range of materials for diverse applications including magnet ics, optics, and sensors. (C) 2001 American Vacuum Society.