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Selectively Grown Heterojunction Laser With Dielectric Optical Confinement

IP.com Disclosure Number: IPCOM000099612D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Kuech, TF: AUTHOR [+2]

Abstract

Disclosed is a laser structure fabricated using selective epitaxy which produces, in one growth step, a selectively deposited buried heterojunction laser with dielectric optical confinement. In conventional structures, the amount of optical confinement is limited by the small difference in refractive index available using typical materials, i.e., (AlGa)As/GaAs. The dielectric sidewalls used in the proposed structure to bury the heterojunction provide a much larger difference in refrac- tive index and, thus, greater optical confinement. The laser structure is deposited only where desired and is done in one step.

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Selectively Grown Heterojunction Laser With Dielectric Optical Confinement

       Disclosed is a laser structure fabricated using selective
epitaxy which produces, in one growth step, a selectively deposited
buried heterojunction laser with dielectric optical confinement.  In
conventional structures, the amount of optical confinement is limited
by the small difference in refractive index available using typical
materials, i.e., (AlGa)As/GaAs.  The dielectric sidewalls used in the
proposed structure to bury the heterojunction provide a much larger
difference in refrac- tive index and, thus, greater optical
confinement.  The laser structure is deposited only where desired and
is done in one step.

      The substrate is prepared for selective epitaxy by opening
windows in a dielectric mask and then etching trenches which will
contain the laser structure.  A second dielectric layer is deposited
and then etched off using an anisotropic etch to create sidewalls in
the trenches (see Fig. 1a).  The selective growth process will
deposit epitaxial layers only in these unmasked trenches, with no
deposition occurring on the dielectrically-masked regions. The layers
for the laser structure are now deposited in one step.  Because
growth does not occur on the dielectric material, the layers will be
deposited in a planar fashion (Fig. 1b).

      This structure could be used on a conductive substrate
semi-insulating substrate with top contacts, as shown in Fig. 2.  An
...