Advanced techniques for the fabrication of square spiral photonic crystals by glancing angle deposition

Abstract

Using the glancing angle deposition thin film fabrication technique, it is possible to create tailored, three-dimensional periodic square spiral photonic crystals that exhibit a band of forbidden electromagnetic frequencies related to the dimensions of the nanostructures. Typically, when fabricating square spirals by traditional means, several problems arise due to nonuniform shadowing that results in column broadening and the loss of required periodicity for thicker crystals. Through the use of complex substrate motion that imposes greater restrictions on growth and shadowing, many of these problems have been overcome, in particular through the implementation of two new algorithms: the slow corner and the variable angle post methods. These motion algorithms have been implemented in conjunction with square spiral photonic crystal fabrication to provide more uniform spiral structures along with more stringent periodicity across the crystal that will allow for photonic band gap structures with more ideal characteristics.