Submicrometer scale growth morphology control for the making of photonic crystal
structures
E. Gil-Lafon
1
, A. Trassoudaine
1
, D. Castelluci
1
, A. Pimpinelli
1
, R. Saoudi
2
, O. Parriaux
2
,
A. Muravaud
2
, C. Darraud
3
1
LASMEA UMR CNRS 6602, Université Blaise Pascal, Campus Universitaire des Cézeaux,
63177 Aubière Cedex, France
2
LTSI UMR CNRS 5516, 23 rue du Docteur Paul Michelon, 42023 Saint-Etienne Cedex 02,
France
3
IRCOM UMR CNRS 6615, Université de Limoges, 123 avenue A. Thomas,
87060 Limoges Cedex, France
ABSTRACT
The feasibility of micrometer scale dielectric periodic structures by using a single selective
hydride vapour phase epitaxy (HVPE) step was assessed. HVPE is a near-equilibrium growth
process which offers perfect selectivity whatever the pattern design, thus giving rise to a great
flexibility. The HVPE growth is also mainly governed by the intrinsic anisotropy of the surface
kinetics of the crystal. We demonstrate here that micrometer scale dielectric periodic structures,
constituted of perfectly defined 1μm wide GaAs beams alternately stacked with air, can be
grown by selective HVPE by controlling the hierarchy of the growth rates of the low index faces
of the III-V crystal via the growth temperature and the composition of the vapour phase.
Potential of the HVPE growth technic for the making of submicrometer scale structures is finally
discussed.
INTRODUCTION
Since Yablonovitch’s original idea consisting in building periodic material arrangements in
which propagation of photons within particular energy ranges could be forbidden, the study of
photonic band gap (PBG) or photonic crystals (PC) have moved from curiosity to theoretical and
application maturity [1]. The making of artificial optical structures reveals itself an exciting
technical challenge : one must generate one-dimensional (1D), and preferentially two-
dimensional (2D) and three-dimensional (3D) ordered structures presenting periodically
modulated refractive index with low absorption and controlled inclusion of defect states for
confinement. The key problem relies on the technical feasibility of these PC micro- and nano-
structures with a view to reliable industrialized process routes. Today microstructuring
techniques permit the making of high quality optical materials with a significant flexibility. The
most common approach for generating 1D (multilayer stack alternating high and low refractive
indices) or 2D (periodic patterns of air-holes embedded in a matrix) PC semiconductor structures
involves optical UV beam contact and projection lithography, electron and ion beam lithography,
X-ray lithography and advanced etching techniques on a deep submicron scale. Electron-beam
(e-beam) and X-ray lithographies are used to define masks with submicrometer and nanometer
scale periodic features on a substrate such as silicon or III-V semiconductors such as GaAs or
InP that present high-dielectric constants (3.5<n
InP
<4 and 3.8<n
GaAs
<4.5 in the NIR-Vis region).
Z2.3.1 Mat. Res. Soc. Symp. Proc. Vol. 799 © 2004 Materials Research Society