Optimization of Ultra-Thin Pulsed-DC Magnetron Sputtered Aluminum Films for the Technology of Hyperbolic Metamaterials

Abstract

The future applications of hyperbolic metamaterials demand stacks of materials with alternative ultra-thin conductive/dielectric films with good homogeneity of the thickness and reduced roughness level. In this work, the technology of pulsed-DC magnetron sputtering of aluminum was optimized using the Taguchi method in order to fabricate Al films with improved roughness level. The performed structural characterization proved the smaller Al domains and better homogeneity of the surface. The optimized process was used to fabricate a multilayer structure of Al/HfOx as the metamaterial media. The fabricated structures were optically characterized in the UV/VIS range. The presented findings demonstrated the tunability effect of the effective reflectance of the examined stacks. The presented results are promising for the future application of multilayer structures in novel photonic devices based on hyperbolic metamaterials.

Influence of Nonlocality on Transmittance and Reflectance of Hyperbolic Metamaterials

“…It is worth to underline that of graphene and SiN are considered only in terms of their local response and have been chosen only as an example, which helps to demonstrate more general effects arising from the effective nonlocality in an appropriately designed periodic multilayer structure [37]. Technological feasibility of such structures is not impaired with significant difficulties and similar multilayer stacks have already been successfully manufactured [40,41]. Moreover, the chosen materials can be fabricated by means of well-established chemical vapor deposition [42,43] or reactive magnetron sputtering techniques [44,45].…”

Spatial Dispersion in Hypercrystal Distributed Feedback Lasing

“…Note that the considered constituent materials were chosen as an example to present more general phenomena arising from effective nonlocality of periodical HMM structure. However, it is still worth underlining that the general form of considered PHC laser may be fabricated via usage of well-established techniques, i.e., (1) deposition of multilayer HMM structure via ALD [ 46 ] or magnetron sputtering [ 47 ], (2) defining grating of the assumed period of the PHC structure via e.g., electron-beam lithography [ 48 ] or phase-mask lithography [ 49 ], or (3) deposition of the chosen active material via respective technological process [ 42 , 43 , 50 ].…”

Sensitive Aluminum SPR Sensors Prepared by Thermal Evaporation Deposition

“…Different deposition technologies are available for Al thin film deposition, e.g., direct current (DC) magnetron sputtering, epitaxial growth, , electron beam evaporation, and thermal evaporation . Deposition conditions influence the qualities of Al thin films dramatically.…”