GaAs photonic crystals on SiO2 fabricated by very-high-frequency anode-coupled reactive ion etching and wafer bonding

High-aspect-ratio, two-dimensional (2D) air-column GaAs photonic crystals ( PhCs) on SiO2 layers with a lattice constant ranging from 240 nm to 1.0 mum have been fabricated using a novel method combining wafer bonding and low- temperature very-high-frequency (VHF) reactive ion etching (RIE). The obtai ned PhCs exhibit near-field patterns of sixfold symmetry or fourfold symmet ry due to lateral interference, depending on the lattice structure. We have obtained photoluminescence (PL) spectra of PhCs which reveal the low damag e feature of the combined process of low-temperature RIE and wafer bonding. Reflectance spectra exhibit fine structures which originate from the reson ance coupling of the external light to the zone-folded bands of the photoni c structure. This vertical confinement structure, obtained by forming GaAs PhCs on SiO2, is useful for taking advantage of 2D photonic crystals since it prevents photon dissipation from the lattice plane. The fabrication meth od combining low-temperature RIE with wafer bonding is a promising process for developing 2D photonic crystals on SiO2 layers.