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Improved Operating Lifetime of Lasers With Dry-Etched Mirrors

IP.com Disclosure Number: IPCOM000102275D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 42K

Publishing Venue

IBM

Related People

Heuberger, W: AUTHOR [+3]

Abstract

Lasers with dry-etched mirrors can be utilized for a wider variety of applications than cleaved mirror lasers. However, some of the processes used in the fabrication of dry-etched mirrors have a negative effect on device performance, resulting in significantly shorter operating lifetimes. These problems are eliminated or largely reduced by flash-annealing the lasers after etching but before passivation.

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Improved Operating Lifetime of Lasers With Dry-Etched Mirrors

       Lasers with dry-etched mirrors can be utilized for a
wider variety of applications than cleaved mirror lasers. However,
some of the processes used in the fabrication of dry-etched mirrors
have a negative effect on device performance, resulting in
significantly shorter operating lifetimes.  These problems are
eliminated or largely reduced by flash-annealing the lasers after
etching but before passivation.

      During the fabrication of lasers with etched mirrors, the
mirrors are subjected to ion bombardment and chlorine exposure.  The
ion bombardment may introduce crystal damage, while residual chlorine
on the mirrors can cause corrosion. Both of these effects are
detrimental to laser reliability. Furthermore, when removing the etch
mask, the mirrors are subjected to an oxygen ash step which leaves
behind an oxide film also having an adverse effect on the reliability
of the laser mirrors.

      Proposed is a way of reducing these effects by flash-annealing
the lasers after etching but before applying a passivation coating.
The effects of annealing are to reduce or eliminate crystal damage,
and to remove, by evaporation, volatile oxides and chlorides from the
mirror surface.  The annealing conditions are chosen to be such as to
not impact other properties of the lasers.  An example is described
below.

      Lasers with reactive ion beam etched (RIBE) mirrors, from which
the etch mask...