34-36 ICP v2 10/9/09 13:32 Page 35
dry etching industry
rhombus4
Figure 1:
Highly vertical
sidewalls
obtained for an
optimized ICP
dry etching: a),
b), c) SEM
cross-sections
of 3 µm-, 5 µm-
and 10 µm-
wide ridge
waveguides
fabricated in
InP/InGaAsP
wafer; d)
deeply etched
1 µm-wide
optical
waveguide in
InP/AlGaInAs
material; e) 45°
side-view on
the 3.2 mm-
deep sub-
nanosized
feature with the
evidence of
different layer
accomplished at a very high aspect for surface gratings etched deeply between the layers in compositions in
ratio, as shown in Fig. 2. A deeply into the central part of the laser InP/InGaAsP/InGaAs/AlGaInAs InGaAsP-based
etched first-order grating with a ridge. Fig 2b presents an angled- structure with different compositions wafer
period of 236 nm was fabricated in a view SEM micrograph of deeply for constant etching conditions are
3 mm-wide InP/InGaAsP ridge etched 86 nm-wide features in shown both in Fig. 1 and Fig. 2.
waveguide (Fig. 2a). The grating is InP/InGaAsP, where aspect ratios as
etched directly into the sidewall of high as 30 have been obtained. High-aspect ratio ICP dry etching is
the ridge since, with this geometry, it a crucial technological step to
is relatively easy to control the An additional outcome of the properly fabricate intra-cavity
grating strength/ reflectivity. balanced process was equal-rate reflectors in Al-quaternary based
Fabrication of such distributed Bragg etching of all the materials material [1]. Before the fabrication of
reflectors (DBR) is less critical than investigated. Smooth transitions photonic band-gap mirrors the
Figure 2: Results of ICP dry etching of InP/InGaAsP-based nano-sized features: a) deeply etched (3.2 µm) and highly
recessed first-order sidewall grating fabricated in a ridge waveguide; b) SEM micrograph of high aspect ratio (~30)
etching of InP/InGaAsP material
September 2009 www.compoundsemiconductor.net 35
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44