Fabrication of ultrasmooth complementary split ring resonators by an improved template stripping method on SU-8

• Published in: Microelectronic engineering 2012-10, Vol.98, p.363-366
• Main Authors: Liu, Zhe, Xia, Xiaoxiang, Yang, Haifang, Li, Junjie, Li, Wuxia, Gu, Changzhi
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; Collective excitations (including excitons, polarons, plasmons and other charge-density excitations); Complementary split ring resonator; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electric, optical and optoelectronic circuits; Electronic circuits; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronics; Exact sciences and technology; Materials; Metamaterial; Microelectronic fabrication (materials and surfaces technology); Oscillators, resonators, synthetizers; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Surface and interface electron states; Template stripping
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2012.07.039

[Display omitted] ► Template stripping method was improved to fabricate ultrasmooth hollow structures. ► SU-8 was used to peel off Au nanopatterns from silicon template. ► The pre-baking temperature and depth of nanopatterns on template were optimized. ► Nanoscale complementary split ring resonators with a gap of 30nm were obtained. ► The RMS surface roughness of stripped surface was improved from 1.3 to 0.4nm. It has been demonstrated that metamaterials play a very important role in plasmonic devices. The behavior of surface plasmon polaritons (SPPs) is highly related with the roughness of metal/dielectric interface, for instance, a smooth metal surface can largely elongate the propagation length of SPP. In this work, an improved template stripping method is developed to fabricate ultrasmooth metamaterials of nanoscale complementary split ring resonators (CSRRs). By using an ultraviolet photoresist of SU-8 as the adhesive, nanoscale metal CSRR structures with ultrasmooth surface were peeled off from silicon template by employing a combined process of pre-baking, UV irradiation and post-baking. By optimization of the pre-baking temperature and the depth of the nanopatterns, ultrasmooth nanoscale CSRRs with a gap of 30nm were obtained. Our results indicate that the approach of template stripping by implementation of an SU-8 adhesive layer is an effective method to produce elaborated hollow nanostructures with ultrasmooth surface and nanoscale gap, which may have potentials in sensing applications.