Ultrathin membranes in x-cut lithium niobate.
Ion-beam enhanced etching is used to pattern a bulk lithium niobate crystal with ultrathin membranes. By the implementation of an air gap beneath the membrane, high index contrast is achieved. A buried amorphous layer, created by irradiation with He ions, is removed by means of wet chemical etching in hydro-fluoric acid. Membranes having thicknesses down to 200 nm are fabricated. The etched air gaps and the membranes exhibit a uniform thickness over the entire etched area, and their widths can be purposefully adjusted over a wide range by choosing appropriate ion energies and fluences as well as annealing conditions.
Schrempel
Frank
F
Institute of Solid State Physics, Friedrich-Schiller-University Jena, Max-Wien-Platz 1, D-07743 Jena, Germany. Frank.Schrempel@uni-jena.de
Gischkat
Thomas
T
Hartung
Holger
H
Höche
Thomas
T
Kley
Ernst-Bernhard
EB
Tünnermann
Andreas
A
Wesch
Werner
W