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Browse Prior Art Database

Technique to View Electroluminescence Along the Cavity of Packaged Laser Diodes

IP.com Disclosure Number: IPCOM000102034D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 41K

Publishing Venue

IBM

Related People

Blow, V: AUTHOR [+2]

Abstract

A failure analysis procedure is disclosed which allows inspection of the electroluminescence (EL) emission along the cavity of a packaged laser diode. GaAs- and InP-based laser diodes, which are packaged in TO (transistor outline)-type packages, are inspected using this technique.

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Technique to View Electroluminescence Along the Cavity of Packaged Laser Diodes

       A failure analysis procedure is disclosed which allows
inspection of the electroluminescence (EL) emission along the cavity
of a packaged laser diode.  GaAs- and InP-based laser diodes, which
are packaged in TO (transistor outline)-type packages, are inspected
using this technique.

      The EL emission along a laser diode channel is viewed through
the die substrate material using an infrared microscope.  This can
only be accomplished by removing the substrate metallization and
providing electrical connection to power the laser.

      The substrate metallization is removed using a polishing
technique in which the laser diode chip is kept in the TO package.
The laser diode package is positioned in a modified plastic polishing
mount (part number 57X7119 from Berkshire Tool Co.) as shown in the
figure.  A wire is soldered to the package pin that makes electrical
connection to the epitaxial side of the diode.  The entire assembly
is then mounted in epoxy which mechanically supports the laser diode
for mechanical polishing.  Polishing proceeds until the substrate
metallization is removed, leaving the die substrate exposed.

      The assembly is positioned on the infrared microscope stage and
a 1 micron probe, dipped in indium/gallium eutectic, is used to make
ohmic contract to the die substrate.  A Tektronics curve tracer is
used to forward bias the laser.  The micro...