Electrochemical Fabrication of Silicon-Based Micro-Nano-Hybrid Porous Arrays for Hybrid-Lattice Photonic Crystal

Hybrid-lattice photonic crystals have received extensive attention in photonic device applications for their larger photonic band gaps. However, until now it is time-consuming and money-costing to realize large-area fabrication of hybrid photonic crystal structure at the nanoscale. This paper presents a flexible, effective and costless technique for the fabrication of 2D triangular-honeycomb hybrid-lattice photonic crystal with micro-nano-hybrid porous silicon structure based on the partly oxidized porous silicon (POPS) substrate. Self-positioned nanopore array surrounded with micro-sized macropores was achieved by photoelectrochemical etching on POPS substrate following several microelectrochemical system (MEMS) processing steps including chemical-mechanical polishing and KOH etching. A modified space-charge region (SCR) model was proposed to interpret the underlying mechanism of such self-positioned nanopores formation. Moreover, the dependency of the nanopore size on the morphology of the oxidized trenches with bottle-like widths was studied and a bottleneck effect was proposed. Our work suggests a new way of efficient realization of simple, effective and large-area fabrication of 2D hybrid photonic crystals, which is expected to foster the promotion in high performance photonic devices. (c) 2017 The Electrochemical Society. All rights reserved.