Browse Prior Art Database

Damageless Cleaning Process for Semiconductor Laser Back Contact

IP.com Disclosure Number: IPCOM000102358D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Hoh, P: AUTHOR [+3]

Abstract

Semiconductor lasers often require mirror coatings for improved performance. Unfortunately, the electrical back contact of the laser often gets partially covered by the dielectric coating layer. This is then highly detrimental to good soldering and thermal properties, especially for InP lasers whose characteristics strongly depend on temperature. The method described here is aimed at removing the undesired traces of coating on the back contact of semiconductor lasers in an etch process without degrading the mirror performance. The method applies particularly well to lasers which require coating on one side only.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 92% of the total text.

Damageless Cleaning Process for Semiconductor Laser Back Contact

       Semiconductor lasers often require mirror coatings for
improved performance.  Unfortunately, the electrical back contact of
the laser often gets partially covered by the dielectric coating
layer.  This is then highly detrimental to good soldering and thermal
properties, especially for InP lasers whose characteristics strongly
depend on temperature. The method described here is aimed at removing
the undesired traces of coating on the back contact of semiconductor
lasers in an etch process without degrading the mirror performance.
The method applies particularly well to lasers which require coating
on one side only.

      The process is depicted in Fig. 1.  Instead of cleaving the
layered laser structures at a length of L, pieces of length 2L are
used.  They are coated on both sides with the same required coating
(see Fig.  1A).  A reactive ion etch process (RIE) can then be
employed to remove the coating left on the back side simply by
positioning the bars upside down in the reactor.  Since the ions
impinge normal to the surface to be cleaned, there is very little
scattering and the mirrors are unaffected.  In addition, the last
layer of a coating is very often only a protective one which
therefore could be etched slightly without leading to a reflectivity
change.  Once the back contact is cleaned, one proceeds to cleave the
bars in the middle, thereby obtaining two bars with the desir...